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1

Nerve and Nerve Root Biomechanics  

Microsoft Academic Search

\\u000a Together, the relationship between the mechanical response of neural tissues and the related mechanisms of injury provide\\u000a a foundation for defining relevant thresholds for injury. The nerves and nerve roots are biologic structures with specific\\u000a and important functions, and whose response to mechanical loading can have immediate, long-lasting and widespread consequences.\\u000a In particular, when nerves or nerve roots are mechanically

Kristen J. Nicholson; Beth A. Winkelstein

2

Reconstruction of nerve root sheaths for sacral extradural spinal meningeal cysts with spinal nerve root fibers.  

PubMed

This study analyzed the clinical characteristics and outcomes of sacral extradural spinal meningeal cysts with spinal nerve root fibers treated by reconstruction of the nerve root sheaths. The relationships between the cysts and spinal nerve root fibers were examined microscopically, the cysts were partially excised, and the defects were oversewn to reconstruct the nerve root sheaths. The Improved Japanese Orthopedic Association (IJOA) scoring system was used to evaluate preoperative and postoperative neurological function. Thirty-eight patients were included in this study, with a mean age of 41.4 ± 15.57 years. The mean IJOA score was 18.8 ± 1.32 preoperatively and 19.6 ± 0.65 postoperatively, which was a significant difference (t=-3.77, P=0.001). These results indicate a significant improvement in neurological function after surgery. The most significant improvement in neurological function was sensation (z=-2.86, P=0.004), followed by bowel/bladder function (z=-2.31, P=0.02). PMID:24008383

Sun, Jianjun; Wang, Zhenyu; Li, Zhendong; Wu, Haibo; Yen, Ruyu; Zheng, Mei; Chang, Qing; Liu, Isabelle Yisha

2013-11-01

3

Visualization of sacral nerve roots via percutaneous intraspinal navigation (PIN).  

PubMed

A percutaneous technique for visualizing sacral nerve roots is described. A fiberscope was inserted into the subarachnoid space through a sheath that was inserted via a percutaneous lumbar puncture. The sacral nerve roots were identified with endoscopic visualization and x-ray fluoroscopy localization of the endoscope. These images were compared with those obtained from a videoscope, which revealed better imaging. Specific sacral nerve roots can be identified by using a combination of endoscopy and x-ray fluoroscopy. This technique may enable minimally invasive interventions such as lysis of adhesions, arachnoid cyst decompression, selective dorsal rhizotomy, and more selective and precise nerve stimulation electrode placement. PMID:16219858

Fujimoto, Takuya; Giles, Brian P; Replogle, Robert E; Fujimoto, Hitomi; Miller, Susan L; Purdy, Phillip D

2005-10-01

4

[Sacral nerve root cysts. Discussion on the mechanism of nerve root suffering. Apropos of 4 cases].  

PubMed

Low back pain, sciatia or perineal chronic pain are sometimes related to perineural sacral cysts. Surgical treatment is difficult and may lead to pain or neurological worsening. We report four cases of symptomatic perineural cysts; three of them where operated on with two good results and one increasing perineal pain. Anatomical and radiological description are reviewed. From a therapeutical point of view, we can distinguish two clinical types of radicular suffering. Perineural cyst can cause a commun radicular extrinsic compression; in such a case surgical operation will improve radicular pain. The cystic nerve root can present an intrinsic suffering because of on intradural dilaceration. Then surgery must be avoided specially when many roots are involved because it may worsen the pluriradicular suffering. PMID:9686226

Bourgeois, P; Gaillard, S; Chastanet, P; Christiaens, J L

1997-01-01

5

Morphological characteristics of the cranial root of the accessory nerve.  

PubMed

There has been the controversy surrounding the cranial root (CR) of the accessory nerve. This study was performed to clarify the morphological characteristics of the CR in the cranial cavity. Fifty sides of 25 adult cadaver heads were used. The accessory nerve was easily distinguished from the vagus nerve by the dura mater in the jugular foramen in 80% of 50 specimens. The trunk of the accessory nerve from the spinal cord penetrated the dura mater at various distances before entering the jugular foramen. In 20% of the specimens there was no dural boundary. In these cases, the uppermost cranial rootlet of the accessory nerve could be identified by removing the dura mater around the jugular foramen where it joined to the trunk of the accessory nerve at the superior vagal ganglion. The cranial rootlet was formed by union of two to four short filaments emerging from the medulla oblongata (66%) and emerged single, without filament (34%), and usually joined the trunk of the accessory nerve directly before the jugular foramen. The mean number of rootlets of the CR was 4.9 (range 2-9) above the cervicomedullary junction. The CR of the accessory nerve was composed of two to nine rootlets, which were formed by the union of two to four short filaments and joined the spinal root of the accessory nerve. The CR is morphologically distinct from the vagus nerve, confirming its existence. Clin. Anat. 27:1167-1173, 2014. © 2014 Wiley Periodicals, Inc. PMID:25131313

Liu, Hong-Fu; Won, Hyung-Sun; Chung, In-Hyuk; Kim, In-Beom; Han, Seung-Ho

2014-11-01

6

Eight nerve, root nucleus Dolores E. Lpez  

E-print Network

of the CRNs #12;Motoneurons Cochlear Root Neurons PnC Muscles Auditory Startle reflex Cochlear Root Neurons of the CRNs explain its role in the ASR #12;AUDITORY STARTLE REFLEX Sudden and loud sounds (> 90 dB) Rapid. · They can be immunostained and visualized with the protein calbindin Cochlear Root Neurons - Characteristics

Oliver, Douglas L.

7

Extradural Corticosteroid Injection in Management of Lumbar Nerve Root Compression  

PubMed Central

The effect of extradural corticosteroid injection in patients with nerve root compression syndromes associated with degenerative disease of the lumbar intervertebral discs was assessed in a double-blind controlled trial on 100 consecutive inpatients assigned by random allocation to treatment and control groups. Assessment during admission and at three months revealed statistically highly significant differences in respect of relief of pain and resumption of normal occupation in favour of the group treated by extradural injection. This treatment seems to be a valuable adjunct to the management of lumbar nerve root compression syndromes associated with degenerative disc disease. PMID:4577015

Dilke, T. F. W.; Burry, H. C.; Grahame, R.

1973-01-01

8

Unilateral lumbar facet joint hypertrophy causing nerve root irritation.  

PubMed

We present four cases of massive unilateral lumbar facet joint hypertrophy in an otherwise morphologically normal spine. All presented with a combination of low back pain and symptoms of entrapment of a single lumbar nerve root. The abnormality is best visualised by CT scanning and the results of surgical decompression by partial undercutting facetectomy are favourable. PMID:3190129

Wilde, G P; Szypryt, E P; Mulholland, R C

1988-09-01

9

MR Imaging of Spinal Nerve Roots:Techniques, Enhancement Patterns, and Imaging Findings  

Microsoft Academic Search

The purpose of this report was to review the MR techniques, contrast enhancement patterns, and MR imaging findings for the spinal nerve roots. The phenomenon of contrast enhance- ment of the nerve roots and its relationship to disk disease and failed-back-surgery syndrome are discussed. The MR imaging findings for various inflammatory and neoplastic disorders affecting the spinal nerve roots are

Bassem A. Georgy; Ruth D. Snow; John R. HesSelink

10

Characterization of a chondroitin sulfate hydrogel for nerve root regeneration  

NASA Astrophysics Data System (ADS)

Brachial plexus injury is a serious medical problem that affects many patients annually, with most cases involving damage to the nerve roots. Therefore, a chondroitin sulfate hydrogel was designed to both serve as a scaffold for regenerating root neurons and deliver neurotrophic signals. Capillary electrophoresis showed that chondroitin sulfate has a dissociation constant in the micromolar range with several common neurotrophins, and this was determined to be approximately tenfold stronger than with heparin. It was also revealed that nerve growth factor exhibits a slightly stronger affinity for hyaluronic acid than for chondroitin sulfate. However, E8 chick dorsal root ganglia cultured in the presence of nerve growth factor revealed that ganglia cultured in chondroitin sulfate scaffolds showed more robust growth than those cultured in control gels of hyaluronic acid. It is hypothesized that, despite the stronger affinity of nerve growth factor for hyaluronic acid, chondroitin sulfate serves as a better scaffold for neurite outgrowth, possibly due to inhibition of growth by hyaluronic acid chains.

Conovaloff, Aaron; Panitch, Alyssa

2011-10-01

11

Ultrasound and electrical nerve stimulation-guided S1 nerve root block.  

PubMed

A selective lumbosacral nerve root block is generally is performed under X-ray fluoroscopy, which has the disadvantage of radiation exposure and the need for fluoroscopy equipment. In this study, we assessed the effectiveness of ultrasound and nerve stimulation-guided S1 nerve root block on 37 patients with S1 radicular syndrome. With the patient in a prone position, an ultrasound scan was performed by placing the probe parallel to the body axis. The needle was pointed slightly medial from the lateral side of the probe and advanced toward a hyperechoic area in the sacral foramina with ultrasound guidance. Contrast medium was then injected and its dispersion confirmed by fluoroscopy. The acquired contrast images were classified into intraneural, perineural, and paraneural patterns. The significance of differences in the effect of the block among the contrast image patterns was analyzed. After nerve block, decreased sensation at the S1 innervated region and pain relief was achieved in all patients. No significant difference was noted in the effect of the block between perineural and paraneural patterns. In conclusion, this technique provided reliable S1 nerve root block in patients with S1 radicular syndrome and minimized radiation exposure. PMID:23494676

Sato, Masaki; Mikawa, Yasuhito; Matuda, Akiko

2013-10-01

12

Unilateral lumbar facet joint hypertrophy causing nerve root irritation.  

PubMed Central

We present four cases of massive unilateral lumbar facet joint hypertrophy in an otherwise morphologically normal spine. All presented with a combination of low back pain and symptoms of entrapment of a single lumbar nerve root. The abnormality is best visualised by CT scanning and the results of surgical decompression by partial undercutting facetectomy are favourable. Images fig. 1 fig. 2 fig. 3 fig. 4 PMID:3190129

Wilde, G. P.; Szypryt, E. P.; Mulholland, R. C.

1988-01-01

13

Osteochondroma in the lumbar intraspinal canal causing nerve root compression.  

PubMed

Osteochondromas, which are benign bone tumors that usually develop on long bones, tubular bones, are rarely found in the spine. If they are located in the spinal canal, they may cause nerve root or spinal cord compression, which is a rare but potentially catastrophic manifestation of osteochondromas. In this article, we report a case of a 38-year-old man who presented with low back pain, paresthesia, and weakness of the right lower extremity aggravating gradually for 5 months. No family history of this disease can be traced. The L4-L5 level computed tomography scan showed an abnormal bony protrusion arising from the right interior wall of L5 right lamina toward the intraspinal canal. The protrusion compressed the L5 nerve root severely. T2-weighted magnetic resonance imaging (MRI) of the same level revealed that the L5 nerve root and spinal dura mater were notably compressed by the intraspinal extradural exostosis attached to the right lamina of L5. Considering differential diagnosis, lumbar facet synovial cysts must be excluded as they can also cause myeloradiculopathy with the similar mechanism. The tumor, approximately 6x7x11 mm, was identified after laminectomy of the L5 laminae. Postoperative histopathologic examination confirmed our hypothesis of benign osteochondroma. Postoperatively, the patient recovered rapidly in neurological function and was free of symptoms. Surgery is essential to this rare case. Computed tomography and MRI are helpful for the preoperatively precise indication of tumor extent and its relationships with the adjacent. PMID:19301786

Xu, Jun; Xu, Chao-Rui; Wu, Hong; Pan, Hai-le; Tian, Jun

2009-02-01

14

The effect of nerve root lesioning on various somatosensory evoked potentials in the hog.  

PubMed

Somatosensory evoked potentials (SEPs) were recorded at the lumbar spine following stimulation of the tibial nerve (mixed-nerve SEP; MSEP), the sural nerve (specific nerve SEP; SSEP), and the skin corresponding to the L6 and S1 dermatomes (dermatomal field SEP; DSEP-L and DSEP-S) in the hog. To determine the sensitivity of these three SEPs to the single nerve root (S1 root) function, the effects of nerve roots lesioning were investigated. Cutting S1 nerve root reduced the peak-to-peak amplitude of MSEP by only 28% in comparison with baseline values. The relative amplitudes of SSEP, DSEP-L, and DSEP-S were decreased by 46%, 11% and 51%, respectively. When S1 nerve root was left intact and L5, L6, and S2 nerve roots were cut, the relative amplitudes of MSEP, SSEP, DSEP-L, and DSEP-S were decreased to 68%, 73%, 31%, and 74%, respectively. These results indicate that DSEP-S is as sensitive to the function of S1 nerve root as SSEP but the sensitivities of DSEP-S and SSEP are low in the hog. MSEP is shown unsuitable to monitor the single nerve root dysfunction. PMID:8367778

Terada, K; Larson, B J; Owen, J H; Sugioka, Y

1993-06-15

15

Clinical applications of diffusion magnetic resonance imaging of the lumbar foraminal nerve root entrapment  

PubMed Central

Diffusion-weighted imaging (DWI) can provide valuable structural information about tissues that may be useful for clinical applications in evaluating lumbar foraminal nerve root entrapment. Our purpose was to visualize the lumbar nerve root and to analyze its morphology, and to measure its apparent diffusion coefficient (ADC) in healthy volunteers and patients with lumbar foraminal stenosis using 1.5-T magnetic resonance imaging. Fourteen patients with lumbar foraminal stenosis and 14 healthy volunteers were studied. Regions of interest were placed at the fourth and fifth lumbar root at dorsal root ganglia and distal spinal nerves (at L4 and L5) and the first sacral root and distal spinal nerve (S1) on DWI to quantify mean ADC values. The anatomic parameters of the spinal nerve roots can also be determined by neurography. In patients, mean ADC values were significantly higher in entrapped roots and distal spinal nerve than in intact ones. Neurography also showed abnormalities such as nerve indentation, swelling and running transversely in their course through the foramen. In all patients, leg pain was ameliorated after selective decompression (n = 9) or nerve block (n = 5). We demonstrated the first use of DWI and neurography of human lumbar nerves to visualize and quantitatively evaluate lumbar nerve entrapment with foraminal stenosis. We believe that DWI is a potential tool for diagnosis of lumbar nerve entrapment. PMID:20632042

Ohtori, Seiji; Yamashita, Masaomi; Yamauchi, Kazuyo; Suzuki, Munetaka; Orita, Sumihisa; Kamoda, Hiroto; Arai, Gen; Ishikawa, Tetsuhiro; Miyagi, Masayuki; Ochiai, Nobuyasu; Kishida, Shunji; Masuda, Yoshitada; Ochi, Shigehiro; Kikawa, Takashi; Takaso, Masashi; Aoki, Yasuchika; Toyone, Tomoaki; Suzuki, Takane; Takahashi, Kazuhisa

2010-01-01

16

Clinical applications of diffusion magnetic resonance imaging of the lumbar foraminal nerve root entrapment.  

PubMed

Diffusion-weighted imaging (DWI) can provide valuable structural information about tissues that may be useful for clinical applications in evaluating lumbar foraminal nerve root entrapment. Our purpose was to visualize the lumbar nerve root and to analyze its morphology, and to measure its apparent diffusion coefficient (ADC) in healthy volunteers and patients with lumbar foraminal stenosis using 1.5-T magnetic resonance imaging. Fourteen patients with lumbar foraminal stenosis and 14 healthy volunteers were studied. Regions of interest were placed at the fourth and fifth lumbar root at dorsal root ganglia and distal spinal nerves (at L4 and L5) and the first sacral root and distal spinal nerve (S1) on DWI to quantify mean ADC values. The anatomic parameters of the spinal nerve roots can also be determined by neurography. In patients, mean ADC values were significantly higher in entrapped roots and distal spinal nerve than in intact ones. Neurography also showed abnormalities such as nerve indentation, swelling and running transversely in their course through the foramen. In all patients, leg pain was ameliorated after selective decompression (n = 9) or nerve block (n = 5). We demonstrated the first use of DWI and neurography of human lumbar nerves to visualize and quantitatively evaluate lumbar nerve entrapment with foraminal stenosis. We believe that DWI is a potential tool for diagnosis of lumbar nerve entrapment. PMID:20632042

Eguchi, Yawara; Ohtori, Seiji; Yamashita, Masaomi; Yamauchi, Kazuyo; Suzuki, Munetaka; Orita, Sumihisa; Kamoda, Hiroto; Arai, Gen; Ishikawa, Tetsuhiro; Miyagi, Masayuki; Ochiai, Nobuyasu; Kishida, Shunji; Masuda, Yoshitada; Ochi, Shigehiro; Kikawa, Takashi; Takaso, Masashi; Aoki, Yasuchika; Toyone, Tomoaki; Suzuki, Takane; Takahashi, Kazuhisa

2010-11-01

17

Effects of arterial ischemia and venous congestion on the lumbar nerve root in dogs.  

PubMed

The development of radiculopathy in patients with lumbar canal stenosis is thought to be closely related to intraradicular edema resulting from compression. However, there is little agreement as to question which is more essential for intermittent claudication: ischemia or congestion. The aim of the present experimental investigation was to examine the effect of ischemia and congestion on the nerve root using dogs. The aorta was clamped as an ischemia model of the nerve root and the inferior vena cava was clamped as a congestion model at the sixth costal level for 30 min using forceps transpleurally. Measurements of blood flow, partial oxygen pressure, and conduction velocity in the nerve root were repeated over a period of 1 h after release of clamping. Finally, we examined the status of intraradicular blood-nerve barrier under fluorescence and transmission electron microscope. Immediately after clamping of the inferior vena cava, the central venous pressure increased by about four times and marked extravasation of protein tracers was induced in the lumbar nerve root. Blood flow, partial oxygen pressure, and conduction velocity of the nerve root were more severely affected by aorta clamp, but this ischemia model did not show any intraradicular edema. The blood-nerve barrier in the nerve root was more easily broken by venous congestion than by arterial ishemia. In conclusion, venous congestion may be an essential factor precipitating circulatory disturbance in compressed nerve roots and inducing neurogenic intermittent claudication. PMID:18536056

Kobayashi, Shigeru; Takeno, Kenichi; Miyazaki, Tsuyoshi; Kubota, Masafumi; Shimada, Seichior; Yayama, Takafumi; Uchida, Kenzo; Normura, Eiki; Mwaka, Erisa; Baba, Hisatoshi

2008-11-01

18

Upregulation of Ryk expression in rat dorsal root ganglia after peripheral nerve injury  

Microsoft Academic Search

To study changes of Ryk expression in dorsal root ganglia (DRG) after peripheral nerve injury, we set up an animal model of unilateral sciatic nerve lesioned rats. Changes of Ryk protein expression in DRG neurons after unilateral sciatic nerve injury were investigated by immunostaining. Changes of Ryk mRNA were also tested by semi-quantitative PCR concurrently. We found, both at the

Xin Li; Yao-hua Li; Shun Yu; Yaobo Liu

2008-01-01

19

Spinal Nerve Root Haemangioblastoma Associated with Reactive Polycythemia  

PubMed Central

Haemangioblastomas are uncommon tumours that usually occur in the cerebellum and, less commonly, in the intramedullary spinal cord. The extramedullary spinal canal is an uncommon location for these tumours. Also haemangioblastoma at this site is not known to be associated with polycythemia. We present the clinical, imaging, and histological findings of an adult patient with extramedullary spinal haemangioblastoma and reactive polycythemia. Radiography and computed tomography (CT) revealed a medium-sized tumour that most likely arose from an extramedullary spinal nerve root. This tumour appeared to be slow growing as evidenced by the accompanying well-defined bony resorption with a sclerotic rim and mild neural foraminal widening. Magnetic resonance imaging revealed prominent flow voids consistent with tumoural hypervascularity. CT-guided biopsy was performed. Although preoperative angiographic embolisation was technically successful, excessive intraoperative tumour bleeding necessitated tumour debulking rather than complete tumour resection. Histology of the resected specimen revealed haemangioblastoma. Seven months postoperatively, the patients back pain and polycythemia have resolved.

Law, Eric K. C.; Lee, Ryan K. L.; Griffith, James F.; Siu, Deyond Y. W.; Ng, Ho Keung

2014-01-01

20

Ultrasonographic reference sizes of the median and ulnar nerves and the cervical nerve roots in healthy Japanese adults.  

PubMed

The objective of this study was to identify, for practical use, ultrasonographic reference values for nerve sizes at multiple sites, including entrapment and non-entrapment sites along the median and ulnar nerves and among the cervical nerve roots. We verified reliable sites and site-based differences between the reference values. In addition, we found associations between the reference nerve sizes and several physical characteristics (gender, dominant hand, age, height, weight, body mass index [BMI] and wrist circumference). Nerves were measured bilaterally at 26 sites or levels in 60 healthy Japanese adults (29 males; age, 35.4 ± 9.7 y; BMI, 22.3 ± 3.6 kg/m(2); wrist circumference, 16.0 ± 1.3 cm on the right side and 15.9 ± 1.2 cm on the left side). The mean reference nerve sizes were 5.6-9.1 mm(2) along the median nerve, 4.1-6.7 mm(2) along the ulnar nerve and 2.14-3.39 mm among the cervical nerve roots. Multifactorial regression analyses revealed that the physical characteristics most strongly associated with nerve size were age, BMI and wrist circumference at the entrapment sites (F = 7.6, p < 0.01, at the pisiform bone level of the carpal tunnel; F = 15.1, p < 0.001, at the level of Guyon's canal), as well as wrist circumference and gender at the non-entrapment sites (F = 70.6, p < 0.001, along the median nerve; F = 24.7, p < 0.001, along the ulnar nerve). Our results suggest that the factors with the greatest influence on nerve size differed between entrapment and non-entrapment sites. Site-based differences in nerve size were determined using one-way analyses of variance (p < 0.001). Intra- and inter-observer reliability was highest for the median nerve, at both the distal wrist crease and mid-humerus; at the arterial split along the ulnar nerve; and at the fifth cervical nerve root level. No systematic error was indicated by Bland-Altman analysis; the coefficients of variation were 5.5%-9.2% for intra-observer reliability and 7.1%-8.7% for inter-observer reliability. PMID:23830101

Sugimoto, Takamichi; Ochi, Kazuhide; Hosomi, Naohisa; Mukai, Tomoya; Ueno, Hiroki; Takahashi, Tetsuya; Ohtsuki, Toshiho; Kohriyama, Tatsuo; Matsumoto, Masayasu

2013-09-01

21

Role of stenosis of spinal canal in L4-L5 nerve root compression assessed by flexion-extension myelography  

Microsoft Academic Search

Myelographic flexion-extension studies were performed in four groups of 10 patients each, with (A) normal myelogram; (B) bilateral nerve root compression at L4-L5; (C) unilateral nerve root compression at L4-L5 and (D) nerve root compression at L5-S1. The aim of the investigation was to assess the role of spinal stenosis in contributing to nerve root compression. The results indicate that

J. T. Wilmink; L. Penning; W. van den Burg

1984-01-01

22

Clinical applications of diffusion magnetic resonance imaging of the lumbar foraminal nerve root entrapment  

Microsoft Academic Search

Diffusion-weighted imaging (DWI) can provide valuable structural information about tissues that may be useful for clinical\\u000a applications in evaluating lumbar foraminal nerve root entrapment. Our purpose was to visualize the lumbar nerve root and\\u000a to analyze its morphology, and to measure its apparent diffusion coefficient (ADC) in healthy volunteers and patients with\\u000a lumbar foraminal stenosis using 1.5-T magnetic resonance imaging.

Yawara Eguchi; Seiji Ohtori; Masaomi Yamashita; Kazuyo Yamauchi; Munetaka Suzuki; Sumihisa Orita; Hiroto Kamoda; Gen Arai; Tetsuhiro Ishikawa; Masayuki Miyagi; Nobuyasu Ochiai; Shunji Kishida; Yoshitada Masuda; Shigehiro Ochi; Takashi Kikawa; Masashi Takaso; Yasuchika Aoki; Tomoaki Toyone; Takane Suzuki; Kazuhisa Takahashi

2010-01-01

23

Diffusion-weighted magnetic resonance imaging of symptomatic nerve root of patients with lumbar disk herniation  

Microsoft Academic Search

Introduction  Diffusion-weighted imaging (DWI) can provide valuable structural information that may be useful for evaluating pathological\\u000a changes of the lumbar nerve root. Diffusion-weighted magnetic resonance (MR) neurography has recently been introduced as an\\u000a alternative way to visualize nerves, but to date, quantitative DWI and MR neurography have not been applied to evaluate the\\u000a pathology of lumbar nerve roots.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Our purpose was

Yawara Eguchi; Seiji Ohtori; Masaomi Yamashita; Kazuyo Yamauchi; Munetaka Suzuki; Sumihisa Orita; Hiroto Kamoda; Gen Arai; Tetsuhiro Ishikawa; Masayuki Miyagi; Nobuyasu Ochiai; Shunji Kishida; Gen Inoue; Yoshitada Masuda; Shigehiro Ochi; Takashi Kikawa; Tomoaki Toyone; Masashi Takaso; Yasuchika Aoki; Kazuhisa Takahashi

24

The Relation Between Rotation Deformity and Nerve Root Stress in Lumbar Scoliosis  

NASA Astrophysics Data System (ADS)

Even though several finite element models of lumbar spine were introduced, there has been no model including the neural structure. Therefore, the authors made the novel lumbar spine finite element model including neural structure. Using this model, we investigated the relation between the deformity pattern and nerve root stress. Two lumbar models with different types of curve pattern (lateral bending and lateral bending with rotation curve) were made. In the model of lateral bending curves without rotation, the principal compressive nerve root stress on the concave side was greater than the principal tensile stress on the convex side at the apex vertebra. Contrarily, in the lateral bending curve with rotational deformity, the nerve stress on the convex side was higher than that on the concave side. Therefore, this study elicit that deformity pattern could have significantly influence on the nerve root stress in the lumbar spine.

Kim, Ho-Joong; Lee, Hwan-Mo; Moon, Seong-Hwan; Chun, Heoung-Jae; Kang, Kyoung-Tak

25

Transverse ultrasound assessment of median nerve deformation and displacement in the human carpal tunnel during wrist movements.  

PubMed

The symptoms of carpal tunnel syndrome, a compression neuropathy of the median nerve at the wrist, are aggravated by wrist motion, but the effect of these motions on median nerve motion are unknown. To better understand the biomechanics of the abnormal nerve, it is first necessary to understand normal nerve movement. The purpose of this study was to evaluate the deformation and displacement of the normal median nerve at the proximal carpal tunnel level on transverse ultrasound images during different wrist movements, to have a baseline for comparison with abnormal movements. Dynamic ultrasound images of both wrists of 10 asymptomatic volunteers were obtained during wrist maximal flexion, extension and ulnar deviation. To simplify the analysis, the initial and final shape and position of the median nerve were measured and analyzed. The circularity of the median nerve was significantly increased and the aspect ratio and perimeter were significantly decreased in the final image compared with the first image during wrist flexion with finger extension, wrist flexion with finger flexion and wrist ulnar deviation with finger extension (p < 0.01). There were significant differences in median nerve displacement vector between finger flexion, wrist flexion with finger extension and wrist ulnar deviation with finger extension (all p's < 0.001). The mean amplitudes of median nerve motion in wrist flexion with finger extension (2.36 ± 0.79 normalized units [NU]), wrist flexion with finger flexion (2.46 ± 0.84 NU) and wrist ulnar deviation with finger extension (2.86 ± 0.51 NU) were higher than those in finger flexion (0.82 ± 0.33 NU), wrist extension with finger extension (0.77 ± 0.46 NU) and wrist extension with finger flexion (0.81 ± 0.58 NU) (p < 0.0001). In the normal carpal tunnel, wrist flexion and ulnar deviation could induce significant transverse displacement and deformation of the median nerve. PMID:24210862

Wang, Yuexiang; Zhao, Chunfeng; Passe, Sandra M; Filius, Anika; Thoreson, Andrew R; An, Kai-Nan; Amadio, Peter C

2014-01-01

26

Regional donor nerves in the reinnervation of brachial plexus palsy due to upper spinal roots avulsion.  

PubMed

The prognosis for surgical treatment in cases of upper brachial plexus palsy due to spinal roots avulsion is somewhat better than in cases of total palsy. The main reasons are better possibilities for surgical reinnervation using regional donors i.e. the medial pectoral and the thoracodorsal nerves, and a shorter time span for nerve regeneration. Regional donor nerves, alone or in combination with upper intercostals and/or the spinal accessory nerve, were used in 13 cases for the reinnervation of the musculocutaneous and/or the axillary nerves. The value of the regional donors is analysed and compared with that of the spinal accessory and intercostal nerves. The value is documented throughout the results of surgical treatment with a follow-up period of at least 18 months after surgery. PMID:2573856

Samardzic, M; Joksimovic, M; Antunovic, V; Grujicic, D

1989-09-01

27

Diagnostic value of history and physical examination in patients suspected of lumbosacral nerve root compression  

PubMed Central

Objective: To evaluate patient characteristics, symptoms, and examination findings in the clinical diagnosis of lumbosacral nerve root compression causing sciatica. Methods: The study involved 274 patients with pain radiating into the leg. All had a standardised clinical assessment and magnetic resonance (MR) imaging. The associations between patient characteristics, clinical findings, and lumbosacral nerve root compression on MR imaging were analysed. Results: Nerve root compression was associated with three patient characteristics, three symptoms, and four physical examination findings (paresis, absence of tendon reflexes, a positive straight leg raising test, and increased finger-floor distance). Multivariate analysis, analysing the independent diagnostic value of the tests, showed that nerve root compression was predicted by two patient characteristics, four symptoms, and two signs (increased finger-floor distance and paresis). The straight leg raise test was not predictive. The area under the curve of the receiver-operating characteristic was 0.80 for the history items. It increased to 0.83 when the physical examination items were added. Conclusions: Various clinical findings were found to be associated with nerve root compression on MR imaging. While this set of findings agrees well with those commonly used in daily practice, the tests tended to have lower sensitivity and specificity than previously reported. Stepwise multivariate analysis showed that most of the diagnostic information revealed by physical examination findings had already been revealed by the history items. PMID:11971050

Vroomen, P; de Krom, M C T F M; Wilmink, J; Kester, A; Knottnerus, J

2002-01-01

28

Partial third nerve palsy and ocular neuromyotonia from displacement of posterior communicating artery detected by high-resolution MRI.  

PubMed

Ocular neuromyotonia is an unusual condition in which sustained, undesired contraction of one or more extraocular muscles occurs after normal muscle activation. Although most commonly reported after paraseller cranial irradiation for tumor, chronic nonaneurysmal vascular compression of the third nerve can produce partial ocular motor nerve paresis and ocular neuromyotonia. A 75-year-old woman presented with intermittent left-gaze-evoked binocular diplopia. She had an incomplete right third nerve palsy but became symptomatically diplopic and esotropic upon sustained left gaze. High-resolution brain magnetic resonance imaging showed displacement of the right posterior communicating artery and contact with the right third nerve. Gaze-evoked diplopia resolved with carbamazepine, but a partial third nerve paresis remained. PMID:23912769

Cruz, Franz Marie; Blitz, Ari M; Subramanian, Prem S

2013-09-01

29

[Sciatica due to unusual causes: Tarlov cysts and nerve roots anomalies].  

PubMed

Tarlov cysts and nerve roots anomalies usually involve lumbosacral roots and are often asymptomatic. MRI has enabled recognition of many conditions that used to be missed by CT or myelography investigations performed for back and leg pain. However, even without additional compressive impingement (disc hernia, spondylolisthesis or lumbar canal stenosis) these anomalies can be responsible for sciatica, motor deficit and bladder sphincter dysfunction. Tarlov cysts are perinervous dilatations of the dorsal root ganglion. CT and especially MRI can reveal these cysts and their precise relations with the neighboring structures. Delayed filling of the cysts can be visualized on the myelogram. MRI is more sensitive than CT myelography for a positive diagnosis of nerve root anomalies, a differential diagnosis with disc hernia and classification of these anomalies. Surgical treatment is indicated for symptomatic Tarlov cysts and nerve root anomalies resistant to conservative treatment. Better outcome is observed in patients with an additional compressive impingement component. We report two cases of sciatica: one caused by Tarlov cysts diagnosed by MRI and the other by nerve root anomalies diagnosed by CT myelography. In both cases, conservative treatment was undertaken. The clinical, radiological and therapeutic aspects of these disorders are discussed. PMID:18809189

Younes, M; Korbaa, W; Zrour, S; Bejia, I; Touzi, M; Bergaoui, N

2009-03-01

30

Intracisternal Cranial Root Accessory Nerve Schwannoma Associated with Recurrent Laryngeal Neuropathy  

PubMed Central

Intracisternal accessory nerve schwannomas are very rare; only 18 cases have been reported in the literature. In the majority of cases, the tumor origin was the spinal root of the accessory nerve and the tumors usually presented with symptoms and signs of intracranial hypertension, cerebellar ataxia, and myelopathy. Here, we report a unique case of an intracisternal schwannoma arising from the cranial root of the accessory nerve in a 58-year-old woman. The patient presented with the atypical symptom of hoarseness associated with recurrent laryngeal neuropathy which is noted by needle electromyography, and mild hypesthesia on the left side of her body. The tumor was completely removed with sacrifice of the originating nerve rootlet, but no additional neurological deficits. In this report, we describe the anatomical basis for the patient's unusual clinical symptoms and discuss the feasibility and safety of sacrificing the cranial rootlet of the accessory nerve in an effort to achieve total tumor resection. To our knowledge, this is the first case of schwannoma originating from the cranial root of the accessory nerve that has been associated with the symptoms of recurrent laryngeal neuropathy. PMID:25328655

Jin, Sung-Won; Park, Dong-Hyuk; Kang, Shin-Hyuk

2014-01-01

31

Development of a duration threshold for modulating evoked neuronal responses after nerve root compression injury.  

PubMed

Cervical nerve roots are susceptible to compression injuries of various durations. The duration of an applied compression has been shown to contribute to both the onset of persistent pain and also the degree of spinal cellular and molecular responses related to nociception. This study investigated the relationship between peripherally-evoked activity in spinal cord neurons during a root compression and the resulting development of axonal damage. Electrically-evoked spikes were measured in the spinal cord as a function of time during and after (post-compression) a 15 minute compression of the C7 nerve root. Compression to the root significantly (p=0.035) reduced the number of spikes that were evoked over time relative to sham. The critical time for compression to maximally reduce evoked spikes was 6.6±3.0 minutes. A second study measured the post- compression evoked neuronal activity following compression applied for a shorter, sub-threshold time (three minutes). Ten minutes after compression was removed, the discharge rate remained significantly (p=0.018) less than baseline by 58±25% relative to sham after the 15 minute compression, but returned to within 3±33% of baseline after the three minute compression. Axonal damage was evident in the nerve root at day seven after nerve root compression only after a 15 minute compression. These studies demonstrate that even a transient mechanical insult to the nerve root is sufficient to induce sustained neuronal dysfunction and axonal pathology associated with pain, and results provide support that such minor neural tissue traumas can actually induce long-lasting functional deficits. PMID:22869302

Nicholson, Kristen J; Quindlen, Julia C; Winkelstein, Beth A

2011-11-01

32

Differential expression of microRNAs in dorsal root ganglia after sciatic nerve injury.  

PubMed

This study investigated the possible involvement of microRNAs in the regulation of genes that participate in peripheral neural regeneration. A microRNA microarray analysis was conducted and 23 microRNAs were identified whose expression was significantly changed in rat dorsal root ganglia after sciatic nerve transection. The expression of one of the downregulated microRNAs, microRNA-214, was validated using quantitative reverse transcriptase-PCR. MicroRNA-214 was predicted to target the 3'-untranslated region of Slit-Robo GTPase-activating protein 3. In situ hybridization verified that microRNA-214 was located in the cytoplasm of dorsal root ganglia primary neurons and was downregulated following sciatic nerve transection. Moreover, a combination of in situ hybridization and immunohistochemistry revealed that microRNA-214 and Slit-Robo GTPase-activating protein 3 were co-localized in dorsal root ganglion primary neurons. Western blot analysis suggested that Slit-Robo GTPase-activating protein 3 was upregulated in dorsal root ganglion neurons after sciatic nerve transection. These data demonstrate that microRNA-214 is located and differentially expressed in dorsal root ganglion primary neurons and may participate in regulating the gene expression of Slit-Robo GTPase-activating protein 3 after sciatic nerve transection. PMID:25206756

Lu, Anjie; Huang, Zufa; Zhang, Chaoyue; Zhang, Xianfang; Zhao, Jiuhong; Zhang, Haiying; Zhang, Quanpeng; Wu, Song; Yi, Xinan

2014-05-15

33

The effects of epidural application of allografted nucleus pulposus in rats on cytokine expression, limb withdrawal and nerve root discharge  

Microsoft Academic Search

This study investigated cytokine expression, behavioral and neurophysiologic changes in Lewis rats whose lumbar nerve roots were exposed to nucleus pulposus (NP). Allografted NP or fat was implanted over the left L5 nerve root. Sham rats had no NP or fat implantation. Control rats had no surgery. Rats were allowed to survive for 7 days and were tested daily for hind-paw

Srinivasu Kallakuri; Tsuneo Takebayashi; A. Cuneyt Ozaktay; Chaoyang Chen; Shangyou Yang; Paul H. Wooley; John M. Cavanaugh

2005-01-01

34

Peripheral nerve injury triggers noradrenergic sprouting within dorsal root ganglia  

Microsoft Academic Search

IN humans, trauma to a peripheral nerve may be followed by chronic pain syndromes which are only relieved by blockade of the effects of sympathetic impulse traffic1-4. It is presumed that, after the lesion, noradrenaline released by activity of sympathetic postganglionic axons excites primary afferent neurons by activating alpha-adrenoceptors2,5, generating signals that enter the 'pain pathways' of the central nervous

Elspeth M. McLachlan; Wilfrid Jänig; Marshall Devor; Martin Michaelis

1993-01-01

35

Functional testing in lumbar nerve root compression syndromes. An evaluation in patients with normal neurological findings  

Microsoft Academic Search

Summary A functional test using downhill walking was evaluated in relation to the myelopgraphical examination in 33 patients with a suspected lumbar nerve root compression syndrome despite normal neurological findings. Any changes of motor or reflex signs or of straight leg raising were accepted as test results. They were noted in a decision matrix and the positive and negative predictive

O. H. Jensen; V. Kjær Hansen; S. Schmidt-Olsen

1991-01-01

36

Gene Transfer to Dorsal Root Ganglia by Intrathecal Injection: Effects on Regeneration of Peripheral Nerves  

Microsoft Academic Search

Gene delivery to sensory neurons of the dorsal root ganglion (DRG) offers the prospect of developing new clinical interventions against peripheral nerve diseases and disorders. Here we show that genes can be transferred to rat DRG through lumbar intrathecal injection of delivery vectors into the cerebrospinal fluid. Genes could be transferred to DRG using polyethylenimine (PEI)\\/DNA complexes, Lipofectamine 2000\\/DNA complexes,

Xu Wang; Chaoyang Wang; Jieming Zeng; Xiaoyun Xu; Peter Y. K. Hwang; Woon-Chee Yee; Yee-Kong Ng; Shu Wang

2005-01-01

37

Fenestrated brachial vein perforated by the lateral root of median nerve: a case report  

Microsoft Academic Search

Variations of venous pattern in the arm are common. In this case report, we present a variation of brachial vein (BV) and lat- eral root of median nerve (LRMN). During routine educational dissections of axillary region, it was observed that a fenes- trated BV was perforated by LRMN in the right arm of an old male cadaver. LRMN was not

Ahmet Songur; Ramazan Uygur; Sezer Akçer; Muhsin Toktafl

2009-01-01

38

An autopsy case of meningeal carcinomatosis with parenchymal invasion through the cranial and spinal nerve roots.  

PubMed

Meningeal carcinomatosis is a well-known complication of malignant neoplasms. We report a case of meningeal carcinomatosis of 2 months' duration in a 22-year-old man, in whom the initial symptom was gradually worsening headache. Postmortem examination revealed infiltrating adenocarcinoma of the stomach. Carcinoma cells showed diffuse spread to the subarachnoid space of the brain and spinal cord. In many places, subarachnoid tumor cells had infiltrated to the cranial and spinal nerves. Moreover, carcinoma cells in the nerve roots extended to the parenchyma of the brain and spinal cord beyond the CNS-peripheral nervous system junction. These findings suggest that cranial and spinal nerve roots can be a possible route of parenchymal invasion in meningeal carcinomatosis. PMID:24779918

Kon, Tomoya; Funamizu, Yukihisa; Miki, Yasuo; Tomiyama, Masahiko; Baba, Masayuki; Kurotaki, Hidekachi; Wakabayashi, Koichi

2014-10-01

39

A sciatic nerve with three roots and its perforation by the enlarged ischiadic artery.  

PubMed

Knowledge about the variations of the sciatic nerve (SN) is important for many medical science disciplines. Its compression, entrapment or injury of any kind can result in loss of sensation, pain or motor disabilities in the lower limbs. We observed concurrent neurovascular variations in the gluteal region of an adult female cadaver. The SN had three roots as it emerged out of the greater sciatic foramen. The upper root passed above the piriformis; the middle and lower roots passed below the piriformis. The three roots joined to form the SN in the gluteal region. The inferior gluteal artery (IGA) was large, and it passed below the piriformis, between the middle and lower root of the SN. After a tortuous course, this artery continued down as the sciatic/ischiadic artery. The ischiadic artery (IA) was large in size and pierced the SN in the thigh. After piercing the nerve, it terminated by dividing into muscular branches. The inferior gluteal nerve emerged out from the pelvis through the greater sciatic foramen, above the level of the piriformis. The SN in this case was highly predisposed to compression by the piriformis, IGA or IA, which in turn may lead to altered cutaneous sensation or weakness of the muscles. PMID:23959929

Nayak, Satheesha B; George, Bincy M; Mishra, Snigdha

2014-03-01

40

Migratory Reed Warblers Need Intact Trigeminal Nerves to Correct for a 1,000 km Eastward Displacement  

PubMed Central

Several studies have shown that experienced night-migratory songbirds can determine their position, but it has remained a mystery which cues and sensory mechanisms they use, in particular, those used to determine longitude (east–west position). One potential solution would be to use a magnetic map or signpost mechanism like the one documented in sea turtles. Night-migratory songbirds have a magnetic compass in their eyes and a second magnetic sense with unknown biological function involving the ophthalmic branch of the trigeminal nerve (V1). Could V1 be involved in determining east–west position? We displaced 57 Eurasian reed warblers (Acrocephalus scirpaceus) with or without sectioned V1. Sham operated birds corrected their orientation towards the breeding area after displacement like the untreated controls did. In contrast, V1-sectioned birds did not correct for the displacement. They oriented in the same direction after the displacement as they had done at the capture site. Thus, an intact ophthalmic branch of the trigeminal nerve is necessary for detecting the 1,000 km eastward displacement in this night-migratory songbird. Our results suggest that V1 carries map-related information used in a large-scale map or signpost sense that the reed warblers needed to determine their approximate geographical position and/or an east–west coordinate. PMID:23840374

Heyers, Dominik; Mouritsen, Henrik

2013-01-01

41

Motor Function of the Upper-Extremity after Transection of the Second Thoracic Nerve Root during Total En Bloc Spondylectomy  

PubMed Central

Background In total en bloc spondylectomy (TES) of upper thoracic spine including the second thoracic (T2) vertebra, T2 nerve roots are usually transected. In this study, we examined the association between transection of the T2 nerve roots and upper-extremity motor function in patients with upper thoracic TES. Methods We assessed 16 patients who underwent upper thoracic TES with bilateral transection of the T2 nerve roots. Patients were divided into three groups: 3 patients without any processing of T1 and upper nerve roots (T2 group), 7 with extensive dissection of T1 nerve roots (T1–2 group), and 6 with extensive dissection of T1 and upper nerve roots (C–T2 group). Postoperative upper-extremity motor function was compared between the groups. Results Postoperative deterioration of upper-extremity motor function was observed in 9 of the 16 patients (56.3%). Three of the 7 patients in the T1–2 group and all 6 patients in the C–T2 group showed deterioration of upper-extremity motor function, but there was no deterioration in the T2 group. In the T1–2 group, 3 patients showed mild deterioration that did not affect their activities of daily living and they achieved complete recovery at the latest follow-up examination. In contrast, severe dysfunction occurred frequently in the C–T2 group, without recovery at the latest follow-up. Conclusions The transection of the T2 nerve roots alone did not result in upper-extremity motor dysfunction; rather, the dysfunction is caused by the extensive dissection of the T1 and upper nerve roots. Therefore, transection of the T2 nerve roots in upper thoracic TES seems to be an acceptable procedure with satisfactory outcomes. PMID:25333299

Yokogawa, Noriaki; Murakami, Hideki; Demura, Satoru; Kato, Satoshi; Yoshioka, Katsuhito; Hayashi, Hiroyuki; Ishii, Takayoshi; Fujii, Moriyuki; Igarashi, Takashi; Tsuchiya, Hiroyuki

2014-01-01

42

Diffusion tensor imaging and T2 relaxometry of bilateral lumbar nerve roots: feasibility of in-plane imaging  

PubMed Central

Lower back pain is a common problem frequently encountered without specific biomarkers that correlate well with an individual patient's pain generators. MRI quantification of diffusion and T2 relaxation properties may provide novel insight into mechanical and inflammatory changes that occur in lumbosacral nerve roots in patients with lower back pain. Imaging the spinal nerve roots accurately is difficult due to their small caliber and oblique course in all three planes. Two-dimensional in-plane imaging of the lumbosacral nerve roots requires oblique coronal imaging with large field-of-view (FOV) in both dimensions, resulting in severe geometric distortions using single-shot echo planar imaging (EPI) techniques. The present work describes initial success using a reduced-FOV single-shot spin-echo EPI acquisition to obtain in-plane DTI and T2 mapping of the bilateral lumbar nerve roots at the L4 level of healthy subjects, minimizing partial volume effects, breathing artifacts and geometric distortions. A significant variation of DTI and T2 mapping metrics is also reported along the course of the normal nerve root. The FA value is statistically significantly lower in the dorsal root ganglia (0.287 ± 0.068) than in regions more distally in the spinal nerve (0.402 ± 0.040) (p<10?5). The T2 relaxation value is statistically significantly higher in the dorsal root ganglia (78.0 ± 11.9 ms) than in regions more distally in the spinal nerve (59.5 ± 7.4 ms) (p<10?5). Quantification of nerve root DTI and T2 properties using the proposed methodology may identify the specific site of any degenerative and inflammatory changes along the nerve roots of patients with lower back pain. PMID:23208676

Karampinos, Dimitrios C.; Melkus, Gerd; Shepherd, Timothy M.; Banerjee, Suchandrima; Saritas, Emine U.; Shankaranarayanan, Ajit; Hess, Christopher P.; Link, Thomas M.; Dillon, William P.; Majumdar, Sharmila

2013-01-01

43

Spontaneous migration of a redundant nerve root accompanied by absorption of lumbar disk herniation. A case report.  

PubMed

A redundant nerve root is defined as a large, elongated and tortuous nerve root commonly associated with severe lumbar spinal canal stenosis. Elongation of nerve roots as a result of mechanical trapping at stenotic level is assumed to be a possible mechanism. Here we present a case in a patient who showed a redundant nerve root above the level of a lumbar canal stenosis caused by disk herniation and redundancy spontaneously migrating to a lower lumbar stenosis level accompanied by absorption of the herniated disk as shown by magnetic resonance imaging (MRI). A 67-year-old Japanese woman presented with bilateral thigh/leg pain and intermittent claudication. A midsagittal T2-weighted MR image of the lumbar spine revealed severe spinal canal stenosis at the L3-4 and L4-5 levels. At the L3-4 level, central disk herniation compressed the dural tube. An MR image revealed redundant nerve roots just cranial to the severely compressed L3-4 level. A follow-up MRI study revealed regression of disk herniation at the L3-4 level. In contrast, there was no significant change of the stenosis at the L4-5 level. Sagittal T2-weighted MR imaging at follow-up revealed redundant nerve roots just cranial to the L4-5 level, whereas the redundant nerve roots cranial to the L3-4 level had disappeared. The MRI findings of the present case support the "squeeze" hypothesis as causative of redundant nerve roots. PMID:24029099

Koda, M; Rokkaku, T; Mannoji, C; Okamoto, Y; Kon, T; Murakami, M; Furuya, T; Yamazaki, M

2012-11-01

44

Microsurgical anatomy of the denticulate ligaments and their relationship with the axilla of the spinal nerve roots.  

PubMed

The denticulate ligaments (DL), 20 or 21 pairs of meningeal extensions, spread from the lateral aspect of the spinal cord to the internal aspect of the spinal dura mater. The aim of this study is to define the specific relationship of the DL with adjacent axilla of the spinal nerve roots and to investigate the anatomical features of the DLs and their variations. The topographical anatomy of the DLs and their relationships with the adjacent axilla of the spinal nerve roots was examined on 16 formalin-fixed adult cadaveric spinal cords. The distances from the dural attachment of the DL to the axilla of the superior and inferior spinal nerve roots were measured bilaterally at every spinal level. Also the distances from the dural attachment of the DL to the lateral aspect of the spinal cord were measured bilaterally. Cervical DLs showed a triangular shape, while in the thoracic segment the ligament changes the shape to "Y." Also the most caudal DL was identified to be at the L1-2 level. Our study revealed that the distances from the dural attachment of the DL to the superior and inferior spinal nerve root axilla were different at the cervical, upper thoracic and the lower thoracic segments. Both distances to the superior and inferior spinal nerve root axilla were shown to increase from cervical to lower thoracic segments. This study provides a detailed anatomy of the DLs and their relationship with the adjacent spinal nerve root axilla. PMID:23897545

Gürer, Bora; Canbay, Suat; Bozkurt, Melih; Cikla, Ula?; Hananya, Tomer; Okut, Hayrettin; Ba?kaya, Mustafa K

2014-07-01

45

Experimental studies on the effect of chymopapain on nerve root compression caused by intervertebral disk material.  

PubMed

Chymopapain degrades the nucleus pulposus portion of the intervertebral disk of rabbits. The degradation is not grossly visible until 15 days post-injection. Depolymerization of the chondromucoprotein and decreases in the ability of a disk to imbibe fluid, is, in effect, a "chemical decompression" of the nucleur pulposus. The enzyme must come into direct contact with the chondromucoprotein complex of the disk material, and to a significant extent also must reach the area of disk material adjacent to the herniated annulus. Rapid depolymerization of the chondromucoprotein complex on a biomechanical level, and "decompression" of disk material on a biomechanical level can be correlated with relief of pain in all types of disk herniation in human beings. A primary biochemical change in the disk material would lead to a secondary decrease in inflammation if the change led to a "decompression" of the chondromucoprotein. Since the primary effect of chymopapain is on the chondromucoprotein of the disk, beneficial results would not be expected if nerve root compression is due to bony impingement or scar tissue following previous surgery. Chymopapain did not seem to possess any anti-inflammatory properties when bone was used as an irritant under a nerve root. However, this was technically difficult to evaluate and the possibility that chymopapain may also interfere with a chemical mediator of pain or interfere directly with an inflammatory reaction secondary to root compression can not be excluded. PMID:1126086

Krempen, J F; Minnig, D I; Smith, B S

1975-01-01

46

Cervical foraminal selective nerve root block: a 'two-needle technique' with results  

PubMed Central

Several techniques have been described for selective nerve root blocks. We describe a novel ‘two-needle technique’, performed through the postero-lateral route with the patient in lateral position under C-arm guidance. The aim of the current study is to highlight the effectiveness and safety of cervical selective nerve root block for radiculopathy using this technique. We present results of a retrospective 2-year follow-up study of 33 injections carried out on 33 patients with radiculopathy due to cervical disc disease and or foraminal stenosis using this procedure. Patients with myelopathy, gross motor weakness and any other pathology were excluded. The outcome was measured comparing ‘Visual Analogue Score’ (VAS) and ‘Neck Disability Index’ (NDI) before the procedure with those at 6 weeks and 12 months after the procedure. Thirty patients were included in the final analysis. Average pre-operative VAS score was 7.4 (range 5–10), which improved to 2.2 (range 0–7) at 6 weeks and 2.0 (range 0–4) at 1 year and the mean NDI score prior to intervention was 66.9 (range 44–84), which improved to 31.7 (range 18–66) at 6 weeks and 31.1 (range 16–48) at 1 year. The improvements were statistically significant. Patients with involvement of C6 or C7 nerve roots responded slightly better at 6 weeks with regards to VAS improvement. Mean duration of radiation exposure during the procedure was 27.8 s (range 10–90 s). Only minor complications were noted—transient dizziness in two and transient nystagmus in one patient. Our ‘two-needle technique’ is a new, safe and effective non-surgical treatment for cervical radiculopathy. PMID:18204941

Gowda, Veda

2008-01-01

47

Cervical foraminal selective nerve root block: a 'two-needle technique' with results.  

PubMed

Several techniques have been described for selective nerve root blocks. We describe a novel 'two-needle technique', performed through the postero-lateral route with the patient in lateral position under C-arm guidance. The aim of the current study is to highlight the effectiveness and safety of cervical selective nerve root block for radiculopathy using this technique. We present results of a retrospective 2-year follow-up study of 33 injections carried out on 33 patients with radiculopathy due to cervical disc disease and or foraminal stenosis using this procedure. Patients with myelopathy, gross motor weakness and any other pathology were excluded. The outcome was measured comparing 'Visual Analogue Score' (VAS) and 'Neck Disability Index' (NDI) before the procedure with those at 6 weeks and 12 months after the procedure. Thirty patients were included in the final analysis. Average pre-operative VAS score was 7.4 (range 5-10), which improved to 2.2 (range 0-7) at 6 weeks and 2.0 (range 0-4) at 1 year and the mean NDI score prior to intervention was 66.9 (range 44-84), which improved to 31.7 (range 18-66) at 6 weeks and 31.1 (range 16-48) at 1 year. The improvements were statistically significant. Patients with involvement of C6 or C7 nerve roots responded slightly better at 6 weeks with regards to VAS improvement. Mean duration of radiation exposure during the procedure was 27.8 s (range 10-90 s). Only minor complications were noted-transient dizziness in two and transient nystagmus in one patient. Our 'two-needle technique' is a new, safe and effective non-surgical treatment for cervical radiculopathy. PMID:18204941

Kumar, Naresh; Gowda, Veda

2008-04-01

48

[Traumatic cord and nerve root injuries: imaging features at the acute and chronic phases].  

PubMed

Cord injuries are frequent and severe lesions resulting in significant disability, most frequently in younger subjects. The area of cord injured results in clinical syndromes (Brown-Sequard, motor and/or sensory deficit...). Cord and rootlet injuries are best depicted on MRI. Diffusion tensor imaging with tractography enables depiction of the most severe cord lesions and some prediction of tissue viability which may provide an idea of the potential functional prognosis and patient recovery. MRI is optimal to demonstrate areas of cord hemorrhage or compression, partial or complete cord transsection, nerve root avulsion... PMID:20814392

Ducreux, D; Lacour, Mc; Cazejust, J; Benoudiba, F; Sarrazin, Jl

2010-09-01

49

Differentiation of peripheral nerve functions and properties with spectral analysis and Karnovsky-Roots staining: a preliminary study  

PubMed Central

Objective: The purpose of this study was to explore the possibility for analyzing and differentiating between motor and sensory functions of peripheral nerve axons using spectral technology. Methods: 10 ?m slide section of S1 anterior and posterior rabbit spinal nerve roots were made and then stained with Karnovsky-Roots method for molecular hyperspectral imaging microscopy analysis. In addition, Raman spectra data of nerve axons on each slide was collected after Karnovsky-Roots staining for 30 minutes. Results: Motor axons were differentiated from sensory axons in a nerve axon section hyperspectral image via Spectral angle mapper algorithm. Raman scatterings could be detected near 2110 cm-1, and 2155 cm-1 in motor axons after Karnvosky-Roots staining. The value of I2100/I1440 in motor axons are significantly different (P0.001) than in sensory axons after staining for 30 minutes. Conclusions: Motor and sensory nerve axons can be differentiated from their counterparts in 30 minutes by using Raman micro-spectroscopy analysis assisted with Karnovsky-Roots staining.

Xu, Qintong; Chen, Zenggan; Li, Qiong; Liu, Haifei; Zhang, Jian; Yao, Wenhua; Zhang, Ren; Li, Qingli; Liu, Hongying; Zhang, Feng; Lineaweaver, William C

2014-01-01

50

Forelimb muscle activity following nerve graft repair of ventral roots in the rat cervical spinal cord.  

PubMed

Current research on the cellular mechanisms of nerve regeneration suggests the application of nerve growth factors at the repair sites to be beneficial. To test the effectiveness of this approach, we performed transections of the C6 and C7 ventral rootlets from their original sites in the spinal cord of 18 rats. We investigated the electrophysiological changes in three groups of rats operated on by different repair strategies. Six rats comprised the control group (G1). In the other 12 rats, 24 rootlets were implanted into the spinal cord by means of an intercostal nerve graft through the pia mater immediately after transection. Six rats (G2) had fibrin glue applied at the incision. The last 6 rats (G3) had grafts with acidic fibroblast growth factor (aFGF) added to the fibrin glue. The rats' functional recovery was evaluated electrophysiologically at 6 weeks and 6 months after the operation. Needle electromyography showed profound fibrillation potentials (Daube's scoring system) in the deltoid, biceps, and triceps of the operated forelimbs in all groups 6 weeks after the operation. After 6 months, there was a significant decrease in the amount of fibrillation potentials in all groups (G1, G2 and G3, p < 0.0001, 0.0001, 0.0009, respectively, generalized estimating equation, repeated measures) and a significantly high probability for motor units present in sampled muscles of G2 and G3 as compared to G1 (log odds ratio in G2 = 51.8316, G3 = 57.4262, generalized estimating equation). We conclude that several cervical roots can regenerate through intercostal nerve grafts applied using fibrin glue. Adding aFGF may increase the efficacy of sprouting. PMID:12052433

Chuang, Tien-Yow; Huang, Ming-Chao; Chen, Kuo-Chih; Chang, Yue-Cune; Yen, Yu-Shu; Lee, Liang-Shong; Cheng, Henrich

2002-06-21

51

Extrachromosomal DNA of pea (Pisum sativum) root-tip cells replicates by strand displacement  

SciTech Connect

In cultured pea roots there is extrachromosomal DNA associated with cells that differentiate from the G/sub 2/ phase of the cell cycle that is absent from those that differentiate from the G/sub 1/ phase. The authors examined this extrachromosomal DNA by electron microscopy and found that it consisted of three types: (i) double-stranded linear molecules with single-stranded branches (74%), (ii) double-stranded molecules without branches (26%), and (iii) free single-stranded molecules. The double-stranded molecules with or without branches were similar in length, having a modal length of 10-15 ..mu..m. The free single-stranded molecules were shorter and had a mean length of 3.8 ..mu..m. The length of the branches attached to the duplex molecules was only slightly less than that of the free form. The duplex molecules with branches were interpreted as configurations reflecting an ongoing strand-displacement process that results in free single-stranded molecules. Finally, measurements on duplex molecules with multiple branches suggested that the extrachromosomal DNA may exist in the form of tandemly repeated sequences. 8 references, 8 figures.

Krimer, D.B.; Van't Hof, J.

1983-04-01

52

Increased Response to Glutamate in Small Diameter Dorsal Root Ganglion Neurons after Sciatic Nerve Injury  

PubMed Central

Glutamate in the peripheral nervous system is involved in neuropathic pain, yet we know little how nerve injury alters responses to this neurotransmitter in primary sensory neurons. We recorded neuronal responses from the ex-vivo preparations of the dorsal root ganglia (DRG) one week following a chronic constriction injury (CCI) of the sciatic nerve in adult rats. We found that small diameter DRG neurons (<30 µm) exhibited increased excitability that was associated with decreased membrane threshold and rheobase, whereas responses in large diameter neurons (>30 µm) were unaffected. Puff application of either glutamate, or the selective ionotropic glutamate receptor agonists alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainic acid (KA), or the group I metabotropic receptor (mGluR) agonist (S)-3,5-dihydroxyphenylglycine (DHPG), induced larger inward currents in CCI DRGs compared to those from uninjured rats. N-methyl-D-aspartate (NMDA)-induced currents were unchanged. In addition to larger inward currents following CCI, a greater number of neurons responded to glutamate, AMPA, NMDA, and DHPG, but not to KA. Western blot analysis of the DRGs revealed that CCI resulted in a 35% increase in GluA1 and a 60% decrease in GluA2, the AMPA receptor subunits, compared to uninjured controls. mGluR1 receptor expression increased by 60% in the membrane fraction, whereas mGluR5 receptor subunit expression remained unchanged after CCI. These results show that following nerve injury, small diameter DRG neurons, many of which are nociceptive, have increased excitability and an increased response to glutamate that is associated with changes in receptor expression at the neuronal membrane. Our findings provide further evidence that glutamatergic transmission in the periphery plays a role in nociception. PMID:24748330

Gong, Kerui; Kung, Ling-Hsuan; Magni, Giulia; Bhargava, Aditi; Jasmin, Luc

2014-01-01

53

Increased response to glutamate in small diameter dorsal root ganglion neurons after sciatic nerve injury.  

PubMed

Glutamate in the peripheral nervous system is involved in neuropathic pain, yet we know little how nerve injury alters responses to this neurotransmitter in primary sensory neurons. We recorded neuronal responses from the ex-vivo preparations of the dorsal root ganglia (DRG) one week following a chronic constriction injury (CCI) of the sciatic nerve in adult rats. We found that small diameter DRG neurons (<30 µm) exhibited increased excitability that was associated with decreased membrane threshold and rheobase, whereas responses in large diameter neurons (>30 µm) were unaffected. Puff application of either glutamate, or the selective ionotropic glutamate receptor agonists alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainic acid (KA), or the group I metabotropic receptor (mGluR) agonist (S)-3,5-dihydroxyphenylglycine (DHPG), induced larger inward currents in CCI DRGs compared to those from uninjured rats. N-methyl-D-aspartate (NMDA)-induced currents were unchanged. In addition to larger inward currents following CCI, a greater number of neurons responded to glutamate, AMPA, NMDA, and DHPG, but not to KA. Western blot analysis of the DRGs revealed that CCI resulted in a 35% increase in GluA1 and a 60% decrease in GluA2, the AMPA receptor subunits, compared to uninjured controls. mGluR1 receptor expression increased by 60% in the membrane fraction, whereas mGluR5 receptor subunit expression remained unchanged after CCI. These results show that following nerve injury, small diameter DRG neurons, many of which are nociceptive, have increased excitability and an increased response to glutamate that is associated with changes in receptor expression at the neuronal membrane. Our findings provide further evidence that glutamatergic transmission in the periphery plays a role in nociception. PMID:24748330

Gong, Kerui; Kung, Ling-Hsuan; Magni, Giulia; Bhargava, Aditi; Jasmin, Luc

2014-01-01

54

Do L5 and S1 nerve root compressions produce radicular pain in a dermatomal pattern?  

PubMed

STRUCTURED ABSTRACT: Study Design. Observational case series.Objective. To compare the pattern of distribution of radicular pain with published dermatome charts.Summary of Background Data. Dermatomal charts vary, and previous studies have demonstrated significant individual subject variation.Methods. Patients with radiologically and surgically proven nerve root compression caused by prolapsed intervertebral disc completed computerised diagrams of the distribution of pain and pins and needles. 98 patients had L5 compressions and 83 had S1 compressions.Results. The distribution of pain and pins and needles did not correspond well with dermatomal patterns. Of those patients with L5 NRC, only 22 (22.4%) recorded any hits on the L5 dermatome on the front, and only 60 (61.2%) on the back with only 13 (13.3%) on both. Only 1 (1.0%) patient placed >50% of their hits within the L5 dermatome. Of those patients with S1 NRC, only 3 (3.6%) recorded any hits on the S1 dermatome on the front, and only 64 (77.1%) on the back with only 15 (18.1%) on both. No patients placed >50% of their hits within the S1 dermatome. Regarding pins and needles, 27 (29.7%) of L5 patients recorded hits on the front alone, 27 (29.7%) on the back alone and 14 (15.4%) on both. 19 (20.9%) recorded >50% of hits within the L5 dermatome. 3 (3.6%) S1 patients recorded hits on the front alone, 44 (53.0%) on the back alone and 18 (21.7%) on both. 12 (14.5%) recorded >50% of hits within the S1 dermatome.Conclusion. Patient report is an unreliable method of identifying the anatomical source of pain or paraesthesia caused by nerve root compression. PMID:23324941

Taylor, Cs; Coxon, A; Watson, P; Greenough, Cg

2013-01-15

55

The effectiveness of motorised lumbar traction in the management of LBP with lumbo sacral nerve root involvement: a feasibility study  

PubMed Central

Background Traction is commonly used for the treatment of low back pain (LBP), predominately with nerve root involvement; however its benefits remain to be established. The aim of this study was to test the feasibility of a pragmatic randomized controlled trial to compare the difference between two treatment protocols (manual therapy, exercise and advice, with or without traction) in the management of acute/sub acute LBP with 'nerve root' involvement. Methods 30 LBP patients with nerve root pain were recruited and randomly assigned to one of two treatment groups. Primary outcome measures were the: McGill pain questionnaire, Roland Morris disability questionnaire, and the SF36 Questionnaire; recorded at baseline, discharge, 3 and 6 months post-discharge. Results 27 patients completed treatment with a loss of another four patients at follow up. Intention to treat analysis demonstrated an improvement in all outcomes at follow up points but there appeared to be little difference between the groups. Conclusion This study has shown that a trial recruiting patients with 'nerve root' problems is feasible. Further research based upon a fully powered trial is required to ascertain if the addition of traction has any benefit in the management of these patients. Trial Registration Registration number: ISRCTN78417198 PMID:18047650

Harte, Annette A; Baxter, George D; Gracey, Jacqueline H

2007-01-01

56

The comparative performance of Roots type aircraft engine superchargers as affected by change in impeller speed and displacement  

NASA Technical Reports Server (NTRS)

This report presents the results of tests made on three sizes of roots type aircraft engine superchargers. The impeller contours and diameters of these machines were the same, but the length were 11, 8 1/4, and 4 inches, giving displacements of 0.509, 0.382, and 0.185 cubic foot per impeller revolution. The information obtained serves as a basis for the examination of the individual effects of impeller speed and displacement on performance and of the comparative performance when speed and displacement are altered simultaneously to meet definite service requirements. According to simple theory, when assuming no losses, the air weight handled and the power required for a given pressure difference are directly proportional to the speed and the displacement. These simple relations are altered considerably by the losses. When comparing the performance of different sizes of machines whose impeller speeds are so related that the same service requirements are met, it is found that the individual effects of speed and displacement are canceled to a large extent, and the only considerable difference is the difference in the power losses which decrease with increase in the displacement and the accompanying decrease in speed. This difference is small in relation to the net power of the engine supercharger unit, so that a supercharger with short impellers may be used in those applications where the space available is very limited with any considerable sacrifice in performance.

Ware, Marsden; Wilson, Ernest E

1929-01-01

57

Influence of electron-phonon interaction in doped silicon crystals on the root-mean-square dynamic displacement of atoms  

Microsoft Academic Search

The root-mean-square dynamic displacements (begin{array}{*{20}c} - \\\\ {u^2 } \\\\ _{dyn} ) of silicon atoms in single-crystals doped with phosphorus, arsenic, antimony, boron, gallium, and indium are determined experimentally. Characteristic concentration dependences ofbegin{array}{*{20}c} - \\\\ {u^2 } \\\\ _{dyn} are obtained for boron- and phosphorus-doped silicon. A number of experimental facts indicating the existence of electron-phonon interaction in comparison with

M. D. Kapustina; V. A. Panteleev; T. Yu. Markova

1977-01-01

58

Differential effects of distal and proximal nerve lesions on carbonic anhydrase activity in rat primary sensory neurons, ventral and dorsal root axons  

Microsoft Academic Search

The effect of proximal and distal peripheral nerve injuries on the histochemistry of carbonic anhydrase (CA) in rat dorsal root ganglion (DRG) neurons, and myelinated (MyF) dorsal and ventral root fibers was studied. Sciatic neurectomy induced no change. Contrariwise, 7 days after lumbar spinal nerve section the numbers of CA-stained ventral root MyF and DRG cells at the L4 and

J. M. Peyronnard; L. F. Charron; J. P. Messier; J. Lavoie

1988-01-01

59

Root negative gravitropism is accompanied with displacing of columella amyloplasts to the statocyte upper longitudinal cell wall  

NASA Astrophysics Data System (ADS)

Recently it was shown that roots reveal negative gravitropism in the weak combined magnetic field (CMF) with the frequency resonance to the cyclotron frequency of Ca2+ ions. A negative gravitropic reaction in the CMF occurs by a usual physiological process. Experiments in the CMF confirmed that gravitropism is plastid-based and Ca2+ ions participate in this process. Unlike control, amyloplasts-statoliths are not displacing on the lower side of a gravistimulated root but tend to group in the center of a statocyte during 30 min under gravistimulation in the CMF. In an hour of gravistimulation, they are localized near one of the statocyte longitudinal wall. Now we determined that amyloplasts are localized along the statocyte upper longitudinal side. It is of a special interest that a root is bending to the same direction with displacing of amyloplasts: in positive gravitropism - downwards, in negative gravitropism - upwards. On the basis of the obtained data there is a question, what forces promote displacing of amyloplasts against a gravitational vector? In the paper, three possible explanations are discussed: 1) CMF + Ca2+ action on the distribution of elastic forces in cytoskeleton, 2) CMF + Ca2+ action on the distribution of electric field in statocytes, and 3) CMF action on energy and direction of Ca2+ ion rotation according to the ion cyclotron resonance model that can lead to paradoxical Ca2+ redistribution.

Kordyum, Elizabeth; Sobol, Margaryta; Kalinina, Yana; Bogatina, Nina; Kondrachuk, Alexander

60

Cauda equina redundant nerve roots are associated to the degree of spinal stenosis and to spondylolisthesis.  

PubMed

To evaluate the association of redundant nerve roots of cauda equina (RNRCE) with the degree of lumbar spinal stenosis (LSS) and with spondylolisthesis. Method After Institutional Board approval, 171 consecutive patients were retrospectively enrolled, 105 LSS patients and 66 patients without stenosis. The dural sac cross-sectional area (CSA) was measured on T2w axial MRI at the level of L2-3, L3-4 and L4-5 intervertebral discs. Two blinded radiologists classified cases as exhibiting or not RNRCE in MRI. Intra- and inter-observer reproducibility was assessed. Results RNRCE were associated with LSS. RRNCE was more frequent when maximum stenosis<55 mm2. Substantial intra- observer agreement and moderate inter-observer agreement were obtained in the classification of RNRCE. Spondylolisthesis was identified in 27 patients and represented increased risk for RRNCE. Conclusion LSS is a risk factor for RNRCE, especially for dural sac CSA<55 mm2. LSS and spondylolisthesis are independent risk factors for RNRCE. PMID:25337731

Savarese, Leonor Garbin; Ferreira-Neto, Geraldo Dias; Herrero, Carlos Fernando Pereira da Silva; Defino, Helton Luiz Aparecido; Nogueira-Barbosa, Marcello H

2014-10-01

61

Paresis of the L5 nerve root after reduction of low-grade lumbosacral dysplastic spondylolisthesis: a case report.  

PubMed

We present a unique case of a 16-year-old patient who underwent lumbar decompression surgery (L4-S1), low-grade spondylolisthesis reduction surgery at L5-S1, and posterior instrumented fusion from L4 to the pelvis. Neurologic monitoring did not show any sustained changes throughout the operation. The patient was awoken from endotracheal anesthesia with grade 0 muscle function of the left extensor hallucis longus and tibialis anterior muscles resulting in left-sided foot drop. At the last follow-up 12 months after surgery, the patient had partial recovery, with grade 4 muscle function of the left extensor hallucis longus and tibialis anterior muscles. We suggest that early identification with direct nerve root stimulation and wake-up test immediately after reduction of spondylolisthesis will allow prompt release of the reduction and further foramen exploration, and increase the possibility of good postoperative nerve root recovery. PMID:24887052

Lykissas, Marios G; Aichmair, Alexander; Widmann, Roger; Sama, Andrew A

2014-09-01

62

Effects of lipo-prostaglandin E 1 on blood flow and oxygen pressure in lumbo-sacral nerve roots  

Microsoft Academic Search

Lipo-prostaglandin E1 (lipo-PGE1) is reported to be effective in the treatment of intermittent neurogenic claudication associated with lumbar spinal stenosis.\\u000a However, the underlying mechanisms by which lipo-PGE1 improves the neurological symptoms have not been fully clarified. We examined the effects of lipo-PGE1 on blood flow and oxygen pressure in the lumbar nerve roots in cats and in patients with lumbar

Toshihiko Sekikawa; Masazumi Murakami; Kazuhisa Takahashi; Masatsune Yamagata; Koichi Yasuhara; Tetsuharu Nemoto; Toshio Suzuki; Haruaki Nakaya; Hideshige Moriya

1997-01-01

63

Oxygen-ozone therapy for herniated lumbar disc in patients with subacute partial motor weakness due to nerve root compression.  

PubMed

Intradiscal oxygen-ozone (O2-O3) chemonucleolysis is a well-known effective treatment for pain caused by protruding disc disease and nerve root compression due to bulging or herniated disc. The most widely used therapeutic combination is intradiscal injection of an O2-O3 mixture (chemonucleolysis), followed by periradicular injection of O2-O3, steroid and local anaesthetic to enhance the anti-inflammatory and analgesic effect. The treatment is designed to resolve pain and is administered to patients without motor weakness, whereas patients with acute paralysis caused by nerve root compression undergo surgery 24-48h after the onset of neurological deficit. This paper reports on the efficacy of O2-O3 chemonucleolysis associated with anti-inflammatory foraminal injection in 13 patients with low back pain and cruralgia, low back pain and sciatica and subacute partial motor weakness caused by nerve root compression unresponsive to medical treatment. All patients were managed in conjunction with our colleagues in the Neurosurgery Unit of Bellaria Hospital and the IRCCS Institute of Neurological Sciences, Bologna. The outcomes obtained are promising: 100% patients had a resolution of motor weakness, while 84.6% had complete pain relief. Our results demonstrate that O2-O3 therapy can be considered a valid treatment option for this category of patients. PMID:25363257

Dall'Olio, Massimo; Princiotta, Ciro; Cirillo, Luigi; Budai, Caterina; de Santis, Fabio; Bartolini, Stefano; Serchi, Elena; Leonardi, Marco

2014-10-31

64

Slit-Robo GTPase-activating proteins are differentially expressed in murine dorsal root ganglia: modulation by peripheral nerve injury.  

PubMed

The Slit-Robo GTPase-activating proteins (srGAPs) play an important role in neurite outgrowth and axon guidance; however, little is known about its role in nerve regeneration after injury. Here, we studied the expression of srGAPs in mouse dorsal root ganglia (DRG) following sciatic nerve transection (SNT) using morphometric and immunohistochemical techniques. Reverse transcriptase polymerase chain reaction and Western blot analysis indicated that srGAP1 and srGAP3, but not srGAP2, were expressed in normal adult DRG. Following unilateral SNT, elevated mRNA and protein levels of srGAP1 and srGAP3 were detected in the ipsilateral relative to contralateral L(3-4) DRGs from day 3 to day 14. Immunohistochemical results showed that srGAP1 and srGAP3 were largely expressed in subpopulations of DRG neurons in naïve DRGs. However, after SNT, srGAP3 in neurons was significantly increased in the ipsilateral relative to contralateral DRGs, which peaked at day 7 to day 14. Interestingly, DRG neurons with strong srGAP3 labeling also coexpressed Robo2 after peripheral nerve injury. These results suggest that srGAPs are differentially expressed in murine DRG and srGAP3 are the predominant form. Moreover, srGAP3 may participate in Slit-Robo signaling in response to peripheral nerve injury or the course of nerve regeneration. PMID:22271578

Chen, Zhi-Bing; Zhang, Hai-Ying; Zhao, Jiu-Hong; Zhao, Wei; Zhao, Dan; Zheng, Lin-Feng; Zhang, Xian-Fang; Liao, Xiao-Ping; Yi, Xi-Nan

2012-04-01

65

Modified pathological classification of brachial plexus root injury and its MR imaging characteristics.  

PubMed

The authors described a modified pathological classification (PC) of brachial plexus injury (BPI) and its magnetic resonance (MR) imaging characteristics. The reliability and diagnostic accuracy of MR imaging for detecting nerve injury was discussed. Between 2006 and 2010, 86 patients with BPI were managed surgically in our department. Their preoperative MR images and surgical findings were analyzed retrospectively. The PC of BPI was classified into five types: (I) nerve root injury in continuity (including Sunderland grade I-IV injury); (II) postganglionic spinal nerve rupture with or without proximal stump; (III) preganglionic root injury (visible); (IV) preganglionic nerve root injury and postganglionic spinal nerves injury; (V) preganglionic root injury (invisible). The main MR imaging characteristics of BPI included traumatic meningocele, displacement of spinal cord, the absence of nerve root, "Black line" sign, nerve root/trunk injury in continuity, and thickening and edema of nerve root. The accuracy of MR imaging for detecting C5, C6, C7, C8, and T1 nerve roots injury were 93.3, 95.2, 92.3, 84, and 74.4%, respectively. The modified PC provides a detailed description of nerve root injury in BPI, and MR imaging technique is a reliable method for detecting nerve root injury. PMID:24163228

Yang, Jiantao; Qin, Bengang; Fu, Guo; Li, Ping; Zhu, Qingtang; Liu, Xiaolin; Zhu, Jiakai; Gu, Liqiang

2014-03-01

66

microRNA-222 Targeting PTEN Promotes Neurite Outgrowth from Adult Dorsal Root Ganglion Neurons following Sciatic Nerve Transection  

PubMed Central

Dorsal root ganglia (DRG) neurons spontaneously undergo neurite growth after nerve injury. MicroRNAs (miRNAs), as small, non-coding RNAs, negatively regulate gene expression in a variety of biological processes. The roles of miRNAs in the regulation of responses of DRG neurons to injury stimuli, however, are not fully understood. Here, microarray analysis was performed to profile the miRNAs in L4-L6 DRGs following rat sciatic nerve transection. The 26 known miRNAs were differentially expressed at 0, 1, 4, 7, 14 d post injury, and the potential targets of the miRNAs were involved in nerve regeneration, as analyzed by bioinformatics. Among the 26 miRNAs, microRNA-222 (miR-222) was our research focus because its increased expression promoted neurite outgrowth while it silencing by miR-222 inhibitor reduced neurite outgrowth. Knockdown experiments confirmed that phosphatase and tensin homolog deleted on chromosome 10 (PTEN), a major inhibitor of nerve regeneration, was a direct target of miR-222 in DRG neurons. In addition, we found that miR-222 might regulate the phosphorylation of cAMP response element binding protein (CREB) through PTEN, and c-Jun activation might enhance the miR-222 expression. Collectively, our data suggest that miR-222 could regulate neurite outgrowth from DRG neurons by targeting PTEN. PMID:23028614

Wang, Yongjun; Gong, Leilei; Tang, Xiaoyan; Yu, Bin; Gu, Xiaosong; Ding, Fei

2012-01-01

67

The Influence of Random Element Displacement on DOA Estimates Obtained with (Khatri-Rao-)Root-MUSIC.  

PubMed

Although a wide range of direction of arrival (DOA) estimation algorithms has been described for a diverse range of array configurations, no specific stochastic analysis framework has been established to assess the probability density function of the error on DOA estimates due to random errors in the array geometry. Therefore, we propose a stochastic collocation method that relies on a generalized polynomial chaos expansion to connect the statistical distribution of random position errors to the resulting distribution of the DOA estimates. We apply this technique to the conventional root-MUSIC and the Khatri-Rao-root-MUSIC methods. According to Monte-Carlo simulations, this novel approach yields a speedup by a factor of more than 100 in terms of CPU-time for a one-dimensional case and by a factor of 56 for a two-dimensional case. PMID:25393783

Inghelbrecht, Veronique; Verhaevert, Jo; van Hecke, Tanja; Rogier, Hendrik

2014-01-01

68

Three-Dimensional Analysis of Nuclear Size, Shape and Displacement in Clover Root Cap Statocytes from Space and a Clinostat  

NASA Technical Reports Server (NTRS)

Under normal (l-g) conditions the statocytes of root caps have a characteristic polarity with the nucleus in tight association with the proximal cell wall; but, in altered gravity environments including microgravity (mu-g) and the clinostat (c-g) movement of the nucleus away from the proximal cell wall is not uncommon. To further understand the cause of gravity-dependent nuclear displacement in statocytes, three-dimensional cell reconstruction techniques were used to precisely measure the volumes, shapes, and positions of nuclei in white clover (Trifolium repens) flown in space and rotated on a clinostat. Seeds were germinated and grown for 72 hours aboard the Space Shuttle (STS-63) in the Fluid Processing Apparatus (BioServe Space Technologies, Univ. of Colorado, Boulder). Clinorotation experiments were performed on a two-axis clinostat (BioServe). Computer reconstruction of selected groups of statocytes were made from serial sections (0.5 microns thick) using the ROSS (Reconstruction Of Serial Sections) software package (Biocomputation Center, NASA Ames Research Center). Nuclei were significantly displaced from the tops of cells in mu-g (4.2 +/- 1.0 microns) and c-g (4.9 +/- 1.4 microns) when compared to l-g controls (3.4 +/- 0.8 gm); but, nuclear volume (113 +/- 36 cu microns, 127 +/- 32 cu microns and 125 +/- 28 cu microns for l-g, mu-g and c-g respectively) and the ratio of nuclear volume to cell volume (4.310.7%, 4.211.0% and 4.911.4% respectively) were not significantly dependent on gravity treatment (ANOVA; alpha = 0.05). Three-dimensional analysis of nuclear shape and proximity to the cell wall, however, showed that nuclei from l-g controls appeared ellipsoidal while those from space and the clinostat were more spherically shaped. This change in nuclear shape may be responsible for its displacement under altered gravity conditions. Since the cytoskeleton is known to affect nuclear polarity in root cap statocytes, those same cytoskeletal elements could also control nuclear shape. This alteration in nuclear shape and position in mu-g and c-g when compared to l-g may lead to functional differences in the gravity signaling systems of plants subjected to altered gravity environments.

Smith, J.D.; Todd, P. W.; Staehelin, L. A.; Holton, Emily (Technical Monitor)

1997-01-01

69

Sciatic Nerve Transection Triggers Release and Intercellular Transfer of a Genetically Expressed Macromolecular Tracer in Dorsal Root Ganglia  

PubMed Central

We recently developed a genetic transneuronal tracing approach that allows for the study of circuits that are altered by nerve injury. We generated transgenic (ZW-X) mice in which expression of a transneuronal tracer, wheat germ agglutinin (WGA), is induced in primary sensory neurons, but only after transection of their peripheral axon. By following the transneuronal transport of the tracer into the central nervous system (CNS) we can label the circuits that are engaged by the WGA-expressing damaged neurons. Here we used the ZW-X mouse line to analyze dorsal root ganglia (DRG) for intraganglionic connections between injured sensory neurons and their neighboring “intact” neurons. Because neuropeptide Y (NPY) expression is strongly induced in DRG neurons after peripheral axotomy, we crossed the ZW-X mouse line with a mouse that expresses Cre recombinase under the influence of the NPY promoter. As expected, sciatic nerve transection triggered WGA expression in NPY-positive DRG neurons, most of which are of large diameter. As expected, double labeling for ATF-3, a marker of cell bodies with damaged axons, showed that the tracer predominated in injured (i.e., axotomized) neurons. However, we also found the WGA tracer in DRG cell bodies of uninjured sensory neurons. Importantly, in the absence of nerve injury there was no intraganglionic transfer of WGA. Our results demonstrate that intraganglionic, cell-to-cell communication, via transfer of large molecules, occurs between the cell bodies of injured and neighboring noninjured primary afferent neurons. PMID:21484801

Braz, Joao M.; Ackerman, Larry; Basbaum, Allan I.

2013-01-01

70

Neuromodulation through sacral nerve roots 2 to 4 with a Finetech-Brindley sacral posterior and anterior root stimulator  

Microsoft Academic Search

Study design: Investigation of five patients receiving an implant, using laboratory cystometry and self-catheterisation at home.Objectives: To use the established Finetech-Brindley sacral root stimulator to increase bladder capacity by neuromodulation, eliminating the need for posterior rhizotomy, as well as achieving bladder emptying by neurostimulation.Setting: Spinal Injuries Unit, Royal National Orthopaedic Hospital, Stanmore, Middlesex, UK.Methods: Five patients underwent implantation of a

APS Kirkham; SL Knight; ATM Casey; PJR Shah

2002-01-01

71

Persistence of attacks of cluster headache after trigeminal nerve root section  

Microsoft Academic Search

Summary Cluster headache is a strictly unilateral headache that occurs in association with cranial autonomic features. We report a patient with a trigeminal nerve section who continued to have attacks. A 59-year-old man described a 14-year history of left-sided episodes of excruciating pain centred on the retro-orbital and orbi- tal regions. These episodes lasted 1-4 h, recurring 2-3 times daily.

Manjit S. Matharu; Peter J. Goadsby

2002-01-01

72

Ultrasound guided selective cervical nerve root block and superficial cervical plexus block for surgeries on the clavicle  

PubMed Central

We report the anaesthetic management of two cases involving surgeries on the clavicle, performed under superficial cervical plexus block and selective C5 nerve root block under ultrasound (US) guidance, along with general anaesthesia. Regional analgesia for clavicular surgeries is challenging. Our patients also had significant comorbidities necessitating individualised approach. The first patient had a history of emphysema, obesity, and was allergic to morphine and hydromorphone. The second patient had clavicular arthritis and pain due to previous surgeries. He had a history of smoking, Stevens-Johnson syndrome, along with daily marijuana and prescription opioid use. Both patients had an effective regional block and required minimal supplementation of analgesia, both being discharged on the same day. Interscalene block with its associated risks and complications may not be suitable for every patient. This report highlights the importance of selective regional blockade and also the use of US guidance for an effective and safe block. PMID:25024480

Shanthanna, Harsha

2014-01-01

73

The effects of anticonvulsants on 4-aminopyridine-induced bursting: in vitro studies on rat peripheral nerve and dorsal roots.  

PubMed Central

1. Aminopyridines have been used as beneficial symptomatic treatments in a variety of neurological conditions including multiple sclerosis but have been associated with considerable toxicity in the form of abdominal pain, paraesthesias and (rarely) convulsions. 2. Extracellular and intracellular recording was used to characterize action potentials in rat sciatic nerves and dorsal roots and the effects of 4-aminopyridine (4-AP). 3. In sciatic nerve trunks, 1 mM 4-AP produced pronounced after potentials at room temperature secondary to regenerative firing in affected axons (5-10 spikes per stimulus). At physiological temperatures, after potentials (2-3 spikes) were greatly attenuated in peripheral axons. 4. 4-AP evoked more pronounced and prolonged after discharges in isolated dorsal roots at 37 degrees C (3-5.5 mV and 80-100 ms succeeded by a smaller inhibitory/depolarizing voltage shift) which were used to assess the effects of anticonvulsants. 5. Phenytoin, carbamazepine and lamotrigine dose-dependently reduced the area of 4-AP-induced after potentials at 100 and 320 microM but the amplitude of compound action potentials (evoked at 0.5 Hz) was depressed in parallel. 6. The tonic block of sensory action potentials by all three drugs (at 320 microM) was enhanced by high frequency stimulation (5-500 Hz). 7. The lack of selectivity of these frequency-dependent Na+ channel blockers for burst firing compared to low-frequency spikes, is discussed in contrast to their effects on 4-AP-induced seizures and paroxysmal activity in CNS tissue (which is associated with large and sustained depolarizing plateau potentials). 8. In conclusion, these in vitro results confirm the marked sensitivity of sensory axons to 4-AP (the presumptive basis for paraesthesias). Burst firing was not preferentially impaired at relatively high concentrations suggesting that anticonvulsants will not overcome the toxic peripheral actions of 4-AP in neurological patients. PMID:8821551

Lees, G.

1996-01-01

74

Correlation Between Vasodilatation and Secretion in the Lacrimal Gland Elicited by Stimulation of the Cornea and Facial Nerve Root of the Cat  

Microsoft Academic Search

Purpose. To determine whether reflex vasodilatation can be elicited in the cat lacrimal gland by electrical stimulation of the cornea, whether the vasodilatation elicited by electrical stimula- tion of the facial nerve root found to be the efferent arm of the cornea-lacrimal gland reflex pathway correlates with the evoked secretion in the lacrimal gland, and what kind of receptors and

Tomoki Yasui; Keishiro Karita; Hiroshi Izumi; Makoto Tamai

75

Translaminar Microendoscopic Herniotomy for Cranially Migrated Lumbar Disc Herniations Encroaching on the Exiting Nerve Root in the Preforaminal and Foraminal Zones  

PubMed Central

Study Design Case series. Purpose The aim of this study was to describe translaminar microendoscopic herniotomy (TL-MEH) for cranially migrated lumbar disc herniations encroaching on the exiting nerve root in the preforaminal and foraminal zones and to report preliminary results of the procedure. Overview of Literature Conventional interlaminar approaches for preforaminal and foraminal lumbar disc herniations result in extensive removal of the lamina and facet joint to remove disc fragments safely. More destructive approaches increase the risk of postoperative segmental instability. Methods TL-MEH is a minimally invasive procedure for herniotomy via the translaminar approach using a microendoscopic technique. TL-MEH was performed in seven patients with a cranially migrated lumbar disc herniation encroaching on the exiting nerve root. The disc fragments were located in the preforaminal zone in four patients, and in the preforaminal and foraminal zones in three. Results All patients experienced immediate relief from symptoms after surgery and satisfactory results at the final follow-up. Surgical complications, such as a dural tear, nerve injury, and surgical site infection, were not investigated. Conclusions TL-MEH seemed to be an effective and safe alternative minimally invasive surgical option for patients with a cranially migrated lumbar disc herniation encroaching the exiting nerve root in the preforaminal and foraminal zones. PMID:24066214

Tono, Osamu; Senba, Hideyuki; Kitamura, Takahiro; Komiya, Norihiro; Oga, Masayoshi; Shidahara, Satoshi

2013-01-01

76

Radiological Significance of Ligamentum Flavum Hypertrophy in the Occurrence of Redundant Nerve Roots of Central Lumbar Spinal Stenosis  

PubMed Central

Objective There were previous reports of redundant nerve roots (RNRs) focused on their clinical significance and pathogenesis. In this study, we investigated the significant radiologic findings that correlate with RNRs occurrence. These relations would provide an advanced clue for clinical significance and pathogenesis of RNRs. Methods Retrospective research was performed with data from 126 patients who underwent surgery for central lumbar spinal stenosis (LSS). Finally, 106 patients with common denominators (inter-observer accuracy : 84%) were included on this study. We divided the patients into two groups by MRI, patients with RNRs and those with no RNRs (NRNRs). Comparative analyses were performed with clinical and radiologic parameters. Results RNRs were found in 45 patients (42%) with central LSS. There were no statistically significant differences between the two groups in severity of symptoms. On the other hand, we found statistically significant differences in duration of symptom and number of level included (p<0.05). In the maximal stenotic level, ligamentum flavum (LF) thickness, LF cross-sectional area (CSA), dural sac CSA, and segmental angulation are significantly different in RNRs group compared to NRNRs group (p<0.05). Conclusion RNRs patients showed clinically longer duration of symptoms and multiple levels included. We also confirmed that wide segmental angulation and LF hypertrophy play a major role of the development of RNRs in central LSS. Together, our results suggest that wide motion in long period contribute to LF hypertrophy, and it might be the key factor of RNRs formation in central LSS. PMID:23115664

Hur, Junseok W; Hur, Junho K; Kwon, Taek-Hyun; Park, Youn Kwan; Chung, Hung Seob

2012-01-01

77

Multi-scale simulations predict responses to non-invasive nerve root stimulation  

NASA Astrophysics Data System (ADS)

Objective. Established biophysical neurone models have achieved limited success in reproducing electrophysiological responses to non-invasive stimulation of the human nervous system. This is related to our insufficient knowledge of the induced electric currents inside the human body. Despite the numerous research and clinical applications of non-invasive stimulation, it is still unclear which internal sites are actually affected by it. Approach. We performed multi-scale computer simulations that, by making use of advances in computing power and numerical algorithms, combine a microscopic model of electrical excitation of neurones with a macroscopic electromagnetic model of the realistic whole-body anatomy. Main results. The simulations yield responses consistent with those experimentally recorded following magnetic and electrical motor root stimulation in human subjects, and reproduce the observed amplitudes and latencies for a wide variety of stimulation parameters. Significance. Our findings demonstrate that modern computational techniques can produce detailed predictions about which and where neurones are activated, leading to improved understanding of the physics and basic mechanisms of non-invasive stimulation and enabling potential new applications that make use of improved targeting of stimulation.

Laakso, Ilkka; Matsumoto, Hideyuki; Hirata, Akimasa; Terao, Yasuo; Hanajima, Ritsuko; Ugawa, Yoshikazu

2014-10-01

78

Rehabilitation Considerations of a Brachial Plexus Injury with Complete Avulsion of C5 and C6 Nerve Roots in a College Football Player  

PubMed Central

Severe brachial plexus injuries are rare in sports, but they have catastrophic results with a significant loss of function in the involved upper extremity. Nerve root avulsions must be timely managed with prompt evaluation, accurate diagnosis, and surgical treatment to optimize the potential for a functional outcome. This case report describes the mechanism of injury, diagnostic evolution, surgical management, and rehabilitation of a college football player who sustained a traumatic complete nerve root avulsion of C5 and C6 (upper trunk of the brachial plexus). Diagnostics included clinical evaluation, magnetic resonance imaging, computed tomography myelogram, and electromyogram. Surgical planning included nerve grafting and neurotization (nerve transfer). Rehabilitation goals were to bring the hand to the face (active biceps function), to stabilize the shoulder for abduction and flexion, and to reduce neuropathic pain. Direct current stimulation, bracing, therapeutic exercise, and biofeedback were used to maximize the use of the athlete’s upper extremity. Although the athlete could not return to sport or normal function by most standards, his results were satisfactory in that he regained an ability to perform many activities of daily living. PMID:23015895

Saliba, Susan; Saliba, Ethan N.; Pugh, Kelli F.; Chhabra, Abhinav; Diduch, David

2009-01-01

79

Differential effects of electrical stimulation of sciatic nerve on metabolic activity in spinal cord and dorsal root ganglion in the rat.  

PubMed

Electrical stimulation of the proximal stump of the transected sciatic nerve produces a frequency-dependent activation of glucose utilization, measured with the autoradiographic deoxy [14C]glucose method, in the dorsal horn of the spinal cord but produces no change in glucose utilization in the dorsal root ganglion cells. These results suggest that axon terminals and not the cell bodies are the sites of enhanced metabolic activity during increased functional activity of this pathway. PMID:3862113

Kadekaro, M; Crane, A M; Sokoloff, L

1985-09-01

80

Differential Effects of Electrical Stimulation of Sciatic Nerve on Metabolic Activity in Spinal Cord and Dorsal Root Ganglion in the Rat  

Microsoft Academic Search

Electrical stimulation of the proximal stump of the transected sciatic nerve produces a frequency-dependent activation of glucose utilization, measured with the autoradiographic deoxy[14C]glucose method, in the dorsal horn of the spinal cord but produces no change in glucose utilization in the dorsal root ganglion cells. These results suggest that axon terminals and not the cell bodies are the sites of

Massako Kadekaro; Alison M. Crane; Louis Sokoloff

1985-01-01

81

Nerve growth factor stimulates synthesis of calcitonin gene-related peptide in dorsal root ganglion cells during sensory regeneration in capsaicin-treated rats  

Microsoft Academic Search

Administration of human recombinant nerve growth factor (rhNGF) into one hindpaw of capsaicin-treated rats can locally facilitate the regeneration of calcitonin gene-related peptide (CGRP)-containing primary sensory neurons (Schicho, R., Skofitsch, G., Donnerer, J., 1999. Brain Res. 815, 60–69). In this study we used in situ hybridization histochemistry (ISH) to determine synthesis of CGRP mRNA in lumbar L4 dorsal root ganglion

Rudolf Schicho; Josef Donnerer

1999-01-01

82

Differential Effects of Electrical Stimulation of Sciatic Nerve on Metabolic Activity in Spinal Cord and Dorsal Root Ganglion in the Rat  

NASA Astrophysics Data System (ADS)

Electrical stimulation of the proximal stump of the transected sciatic nerve produces a frequency-dependent activation of glucose utilization, measured with the autoradiographic deoxy[14C]glucose method, in the dorsal horn of the spinal cord but produces no change in glucose utilization in the dorsal root ganglion cells. These results suggest that axon terminals and not the cell bodies are the sites of enhanced metabolic activity during increased functional activity of this pathway.

Kadekaro, Massako; Crane, Alison M.; Sokoloff, Louis

1985-09-01

83

The Impact of Spinal Cord Nerve Roots and Denticulate Ligaments on Cerebrospinal Fluid Dynamics in the Cervical Spine  

PubMed Central

Cerebrospinal fluid (CSF) dynamics in the spinal subarachnoid space (SSS) have been thought to play an important pathophysiological role in syringomyelia, Chiari I malformation (CM), and a role in intrathecal drug delivery. Yet, the impact that fine anatomical structures, including nerve roots and denticulate ligaments (NRDL), have on SSS CSF dynamics is not clear. In the present study we assessed the impact of NRDL on CSF dynamics in the cervical SSS. The 3D geometry of the cervical SSS was reconstructed based on manual segmentation of MRI images of a healthy volunteer and a patient with CM. Idealized NRDL were designed and added to each of the geometries based on in vivo measurments in the literature and confirmation by a neuroanatomist. CFD simulations were performed for the healthy and patient case with and without NRDL included. Our results showed that the NRDL had an important impact on CSF dynamics in terms of velocity field and flow patterns. However, pressure distribution was not altered greatly although the NRDL cases required a larger pressure gradient to maintain the same flow. Also, the NRDL did not alter CSF dynamics to a great degree in the SSS from the foramen magnum to the C1 level for the healthy subject and CM patient with mild tonsillar herniation (?6 mm). Overall, the NRDL increased fluid mixing phenomena and resulted in a more complex flow field. Comparison of the streamlines of CSF flow revealed that the presence of NRDL lead to the formation of vortical structures and remarkably increased the local mixing of the CSF throughout the SSS. PMID:24710111

Heidari Pahlavian, Soroush; Yiallourou, Theresia; Tubbs, R. Shane; Bunck, Alexander C.; Loth, Francis; Goodin, Mark; Raisee, Mehrdad; Martin, Bryn A.

2014-01-01

84

The impact of spinal cord nerve roots and denticulate ligaments on cerebrospinal fluid dynamics in the cervical spine.  

PubMed

Cerebrospinal fluid (CSF) dynamics in the spinal subarachnoid space (SSS) have been thought to play an important pathophysiological role in syringomyelia, Chiari I malformation (CM), and a role in intrathecal drug delivery. Yet, the impact that fine anatomical structures, including nerve roots and denticulate ligaments (NRDL), have on SSS CSF dynamics is not clear. In the present study we assessed the impact of NRDL on CSF dynamics in the cervical SSS. The 3D geometry of the cervical SSS was reconstructed based on manual segmentation of MRI images of a healthy volunteer and a patient with CM. Idealized NRDL were designed and added to each of the geometries based on in vivo measurments in the literature and confirmation by a neuroanatomist. CFD simulations were performed for the healthy and patient case with and without NRDL included. Our results showed that the NRDL had an important impact on CSF dynamics in terms of velocity field and flow patterns. However, pressure distribution was not altered greatly although the NRDL cases required a larger pressure gradient to maintain the same flow. Also, the NRDL did not alter CSF dynamics to a great degree in the SSS from the foramen magnum to the C1 level for the healthy subject and CM patient with mild tonsillar herniation (? 6 mm). Overall, the NRDL increased fluid mixing phenomena and resulted in a more complex flow field. Comparison of the streamlines of CSF flow revealed that the presence of NRDL lead to the formation of vortical structures and remarkably increased the local mixing of the CSF throughout the SSS. PMID:24710111

Heidari Pahlavian, Soroush; Yiallourou, Theresia; Tubbs, R Shane; Bunck, Alexander C; Loth, Francis; Goodin, Mark; Raisee, Mehrdad; Martin, Bryn A

2014-01-01

85

Monitoring of immune cell response to B cell depletion therapy and nerve root injury using SPIO enhanced MRI  

NASA Astrophysics Data System (ADS)

Magnetic resonance (MR) is a robust platform for non-invasive, high-resolution anatomical imaging. However, MR imaging lacks the requisite sensitivity and contrast for imaging at the cellular level. This represents a clinical impediment to greater diagnostic accuracy. Recent advances have allowed for the in vivo visualization of populations and even of individual cells using superparamagnetic iron oxide (SPIO) MR contrast agents. These nanoparticles, commonly manifested as a core of a single iron oxide crystal or cluster of crystals coated in a biocompatible shell, function to shorten proton relaxation times. In MR imaging these constructs locally dephase protons, resulting in a decrease in signal (hypointensity) localized to the region of accumulation of SPIO. In the context of immune cell imaging, SPIO can provide insight into the cellular migration patterns, trafficking, temporal dynamics and progression of diseases and their related pathological states. Furthermore, by visualizing the presence and activity of immune cells, SPIO-enabled cellular imaging can help evaluate the efficacy of therapy in immune disorders. This thesis examines the production, modification and application of SPIO in a range of in vitro and in vivo immune-response-relevant cellular systems. The role of different nanoparticle characteristics including diameter, surface charge and concentration are investigated in the labeling of T cells in culture. Following optimization of SPIO loading conditions for lymphocytes, the effect these particles have on the activation of primary B cells are elucidated. B cells are tracked using a variety of modalities, with and without the application of B cell depleting therapy. This is to evaluate the efficacy of SPIO as in vivo marker for B cell distribution. Unmodified SPIO were applied to monitor macrophage infiltration in a transient nerve root compression model, with implications for neck pain diagnosis and treatment. Nanoparticle accumulation and MR hypointensity was correlated to the presence of activated macrophage at the site of injury. Taken together, the application of SPIO to study nanoparticle uptake in vitro and visualization of immune cells in vivo provide a basis for advanced study and diagnosis of diverse pathologies.

Thorek, Daniel L.

86

Vasodilative effects of prostaglandin E1 derivate on arteries of nerve roots in a canine model of a chronically compressed cauda equina  

PubMed Central

Background Reduction of blood flow is important in the induction of neurogenic intermittent claudication (NIC) in lumbar spinal canal stenosis. PGE1 improves the mean walking distance in patients with NIC type cauda equina compression. PGE1 derivate might be effective in dilating blood vessels and improving blood flow in nerve roots with chronically compressed cauda equina. The aim of this study was to assess whether PGE1 derivate has vasodilatory effects on both arteries and veins in a canine model of chronic cauda equina compression. Methods Fourteen dogs were used in this study. A plastic balloon inflated to 10 mmHg was placed under the lamina of the 7th lumbar vertebra for 1 week. OP-1206-cyclodextrin clathrate (OP-1206-CD: prostaglandin E1 derivate) was administered orally. The blood vessels of the second or third sacral nerve root were identified using a specially designed surgical microscope equipped with a video camera. The diameter of the blood vessels was measured on video-recordings every 15 minutes until 90 minutes after the administration of the PGE1 derivate. Results We observed seven arteries and seven veins. The diameter and blood flow of the arteries was significantly increased compared with the veins at both 60 and 75 minutes after administration of the PGE1 derivate (p < 0.05). Blood flow velocity did not change over 90 minutes in either the arteries or veins. Discussion The PGE1 derivate improved blood flow in the arteries but did not induce blood stasis in the veins. Our results suggest that the PGE1 derivate might be a potential therapeutic agent, as it improved blood flow in the nerve roots in a canine model of chronic cauda equina compression. PMID:18394203

Shirasaka, Masayoshi; Takayama, Bunji; Sekiguchi, Miho; Konno, Shin-ichi; Kikuchi, Shin-ichi

2008-01-01

87

Patients with low back pain differ from those who also have leg pain or signs of nerve root involvement - a cross-sectional study  

PubMed Central

Background Leg pain associated with low back pain (LBP) is recognized as a risk factor for a poor prognosis, and is included as a component in most LBP classification systems. The location of leg pain relative to the knee and the presence of a positive straight leg raise test have been suggested to have clinical implications. To understand differences between such leg pain subgroups, and whether differences include potentially modifiable characteristics, the purpose of this paper was to describe characteristics of patients classified into the Quebec Task Force (QTF) subgroups of: 1) LBP only, 2) LBP and pain above the knee, 3) LBP and pain below the knee, and 4) LBP and signs of nerve root involvement. Methods Analysis of routine clinical data from an outpatient department. Based on patient reported data and clinical findings, patients were allocated to the QTF subgroups and described according to the domains of pain, activity limitation, work participation, psychology, general health and clinical examination findings. Results A total of 2,673 patients aged 18–95 years (median 47) who were referred for assessment of LBP were included. Increasing severity was consistently observed across the subgroups from LBP only to LBP with signs of nerve root involvement although subgroup differences were small. LBP patients with leg pain differed from those with LBP only on a wide variety of parameters, and patients with signs of nerve root involvement had a more severe profile on almost all measures compared with other patients with back-related leg pain. Conclusion LBP patients with pain referral to the legs were more severely affected than those with local LBP, and patients with signs of nerve root involvement were the ones most severily affected. These findings underpin the concurrent validity of the Quebec Task Force Classification. However, the small size of many between-subgroup differences amid the large variability in this sample of cross-sectional data also underlines that the heterogeneity of patients with LBP is more complex than that which can be explained by leg pain patterns alone. The implications of the observed differences also require investigation in longitudinal studies. PMID:23190800

2012-01-01

88

Neuronal calcium-binding proteins 1/2 localize to dorsal root ganglia and excitatory spinal neurons and are regulated by nerve injury  

PubMed Central

Neuronal calcium (Ca2+)-binding proteins 1 and 2 (NECAB1/2) are members of the phylogenetically conserved EF-hand Ca2+-binding protein superfamily. To date, NECABs have been explored only to a limited extent and, so far, not at all at the spinal level. Here, we describe the distribution, phenotype, and nerve injury-induced regulation of NECAB1/NECAB2 in mouse dorsal root ganglia (DRGs) and spinal cord. In DRGs, NECAB1/2 are expressed in around 70% of mainly small- and medium-sized neurons. Many colocalize with calcitonin gene-related peptide and isolectin B4, and thus represent nociceptors. NECAB1/2 neurons are much more abundant in DRGs than the Ca2+-binding proteins (parvalbumin, calbindin, calretinin, and secretagogin) studied to date. In the spinal cord, the NECAB1/2 distribution is mainly complementary. NECAB1 labels interneurons and a plexus of processes in superficial layers of the dorsal horn, commissural neurons in the intermediate area, and motor neurons in the ventral horn. Using CLARITY, a novel, bilaterally connected neuronal system with dendrites that embrace the dorsal columns like palisades is observed. NECAB2 is present in cell bodies and presynaptic boutons across the spinal cord. In the dorsal horn, most NECAB1/2 neurons are glutamatergic. Both NECAB1/2 are transported into dorsal roots and peripheral nerves. Peripheral nerve injury reduces NECAB2, but not NECAB1, expression in DRG neurons. Our study identifies NECAB1/2 as abundant Ca2+-binding proteins in pain-related DRG neurons and a variety of spinal systems, providing molecular markers for known and unknown neuron populations of mechanosensory and pain circuits in the spinal cord. PMID:24616509

Zhang, Ming-Dong; Tortoriello, Giuseppe; Hsueh, Brian; Tomer, Raju; Ye, Li; Mitsios, Nicholas; Borgius, Lotta; Grant, Gunnar; Kiehn, Ole; Watanabe, Masahiko; Uhlen, Mathias; Mulder, Jan; Deisseroth, Karl; Harkany, Tibor; Hokfelt, Tomas G. M.

2014-01-01

89

Electromechanical Nerve Stimulator  

NASA Technical Reports Server (NTRS)

Nerve stimulator applies and/or measures precisely controlled force and/or displacement to nerve so response of nerve measured. Consists of three major components connected in tandem: miniature probe with spherical tip; transducer; and actuator. Probe applies force to nerve, transducer measures force and sends feedback signal to control circuitry, and actuator positions force transducer and probe. Separate box houses control circuits and panel. Operator uses panel to select operating mode and parameters. Stimulator used in research to characterize behavior of nerve under various conditions of temperature, anesthesia, ventilation, and prior damage to nerve. Also used clinically to assess damage to nerve from disease or accident and to monitor response of nerve during surgery.

Tcheng, Ping; Supplee, Frank H., Jr.; Prass, Richard L.

1993-01-01

90

Low Frequency Electroacupuncture Alleviated Spinal Nerve Ligation Induced Mechanical Allodynia by Inhibiting TRPV1 Upregulation in Ipsilateral Undamaged Dorsal Root Ganglia in Rats  

PubMed Central

Neuropathic pain is an intractable problem in clinical practice. Accumulating evidence shows that electroacupuncture (EA) with low frequency can effectively relieve neuropathic pain. Transient receptor potential vanilloid type 1 (TRPV1) plays a key role in neuropathic pain. The study aimed to investigate whether neuropathic pain relieved by EA administration correlates with TRPV1 inhibition. Neuropathic pain was induced by right L5 spinal nerve ligation (SNL) in rats. 2?Hz?EA stimulation was administered. SNL induced mechanical allodynia in ipsilateral hind paw. SNL caused a significant reduction of TRPV1 expression in ipsilateral L5 dorsal root ganglia (DRG), but a significant up-regulation in ipsilateral L4 and L6 DRGs. Calcitonin gene-related peptide (CGRP) change was consistent with that of TRPV1. EA alleviated mechanical allodynia, and inhibited TRPV1 and CGRP overexpressions in ipsilateral L4 and L6 DRGs. SNL did not decrease pain threshold of contralateral hind paw, and TRPV1 expression was not changed in contralateral L5 DRG. 0.001, 0.01?mg/kg TRPV1 agonist 6?-IRTX fully blocked EA analgesia in ipsilateral hind paw. 0.01?mg/kg 6?-IRTX also significantly decreased pain threshold of contralateral paw. These results indicated that inhibition of TRPV1 up-regulation in ipsilateral adjacent undamaged DRGs contributed to low frequency EA analgesia for mechanical allodynia induced by spinal nerve ligation. PMID:23935654

Fang, Jian-Qiao

2013-01-01

91

Laser-Guided Cervical Selective Nerve Root Block with the Dyna-CT: Initial Experience of Three-Dimensional Puncture Planning with an Ex-Vivo Model  

PubMed Central

Background Cervical selective nerve root block (CSNRB) is a well-established, minimally invasive procedure to treat radicular cervical pain. However, the procedure is technically challenging and might lead to major complications. The objective of this study was to evaluate the feasibility of a three-dimensional puncture planning and two-dimensional laser-guidance system for CSNRB in an ex-vivo model. Methods Dyna-CT of the cervical spine of an ex-vivo lamb model was performed with the Artis Zee® Ceiling (Siemens Medical Solutions, Erlangen, Germany) to acquire multiplanar reconstruction images. 15 cervical nerve root punctures were planned and conducted with the syngo iGuide® laser-guidance system. Needle tip location and contrast dye distribution were analyzed by two independent investigators. Procedural, planning, and fluoroscopic time, tract length, and dose area product (DAP) were acquired for each puncture. Results All 15 punctures were rated as successful with 12 punctures on the first attempt. Total procedural time was approximately 5 minutes. Mean planning time for the puncture was 2.03 (±0.39) min. Mean puncture time was 2.16 (±0.32) min, while mean fluoroscopy time was 0.17 (±0.06) min. Mean tract length was 2.68 (±0.23) cm. Mean total DAP was 397.45 (±15.63) µGy m2. Conclusion CSNRB performed with Dyna-CT and the tested laser guidance system is feasible. 3D pre-puncture planning is easy and fast and the laser-guiding system ensures very accurate and intuitive puncture control. PMID:23894448

Al-Zghloul, Mansour; Groden, Christoph; Kerl, Hans U.

2013-01-01

92

Control of leg-powered paraplegic cycling using stimulation of the lumbo-sacral anterior spinal nerve roots.  

PubMed

We investigated leg-powered cycling in a recumbent tricycle for a paraplegic using functional electrical stimulation (FES) with the lumbo-sacral anterior root stimulator implant (LARSI). A female complete T9 paraplegic had a stimulator for the anterior L2 to S2 spinal roots (bilaterally) implanted in 1994. She was provided with equipment for daily FES cycling exercise at home. The cycling controller applies a pattern of stimulation in each of 16 crank angle phases. A 7-bit shaft encoder measures the crank angle with adequate precision. Each pattern was originally chosen to give the greatest propulsive force in that position when there was no motion. However, dynamically, some reduction in co-contraction is needed; also the patterns are applied with a preset advance time. Maximal power is obtained with an advance of 250 ms, which compensates for muscle response delay and accommodates changes in cadence (from about 25 to 85 rpm). With this system, she has cycled 1.2 km at a time on gently undulating road. We found that spinal root stimulation gives sufficient control over the muscles in the legs to produce a fluid cycling gait. We propose that root stimulation for leg cycling exercise may be a practicable and valuable function for paraplegics following spinal cord injury. PMID:12503780

Perkins, Tim A; de N Donaldson, Nick; Hatcher, Neil A C; Swain, Ian D; Wood, Duncan E

2002-09-01

93

Extracellular Nm23H1 stimulates neurite outgrowth from dorsal root ganglia neurons in vitro independently of nerve growth factor supplementation or its nucleoside diphosphate kinase activity  

SciTech Connect

Research highlights: {yields} Extracellular Nm23H1 stimulates nerve growth. {yields} Extracellular Nm23H1 provides pathfinding cues to growth cones. {yields} The neurotrophic activity of Nm23H1 is independent of NDP kinase activity. {yields} The neurotrophic activity of Nm23H1 is independent of NGF. -- Abstract: The nucleoside diphosphate (NDP) kinase, Nm23H1, is a highly expressed during neuronal development, whilst induced over-expression in neuronal cells results in increased neurite outgrowth. Extracellular Nm23H1 affects the survival, proliferation and differentiation of non-neuronal cells. Therefore, this study has examined whether extracellular Nm23H1 regulates nerve growth. We have immobilised recombinant Nm23H1 proteins to defined locations of culture plates, which were then seeded with explants of embryonic chick dorsal root ganglia (DRG) or dissociated adult rat DRG neurons. The substratum-bound extracellular Nm23H1 was stimulatory for neurite outgrowth from chick DRG explants in a concentration-dependent manner. On high concentrations of Nm23H1, chick DRG neurite outgrowth was extensive and effectively limited to the location of the Nm23H1, i.e. neuronal growth cones turned away from adjacent collagen-coated substrata. Nm23H1-coated substrata also significantly enhanced rat DRG neuronal cell adhesion and neurite outgrowth in comparison to collagen-coated substrata. These effects were independent of NGF supplementation. Recombinant Nm23H1 (H118F), which does not possess NDP kinase activity, exhibited the same activity as the wild-type protein. Hence, a novel neuro-stimulatory activity for extracellular Nm23H1 has been identified in vitro, which may function in developing neuronal systems.

Wright, K.T. [Keele University at the RJAH Orthopaedic Hospital, Oswestry, Shropshire (United Kingdom)] [Keele University at the RJAH Orthopaedic Hospital, Oswestry, Shropshire (United Kingdom); Seabright, R.; Logan, A. [Neuropharmacology and Neurobiology, School of Clinical and Experimental Medicine, Birmingham University, Birmingham (United Kingdom)] [Neuropharmacology and Neurobiology, School of Clinical and Experimental Medicine, Birmingham University, Birmingham (United Kingdom); Lilly, A.J.; Khanim, F.; Bunce, C.M. [Biosciences, Birmingham University, Birmingham (United Kingdom)] [Biosciences, Birmingham University, Birmingham (United Kingdom); Johnson, W.E.B., E-mail: w.e.johnson@aston.ac.uk [Life and Health Sciences, Aston University, Birmingham (United Kingdom)] [Life and Health Sciences, Aston University, Birmingham (United Kingdom)

2010-07-16

94

Subtype-specific reduction of Voltage-gated Calcium Current in Medium-Sized Dorsal Root Ganglion Neurons after Painful Peripheral Nerve Injury  

PubMed Central

Sensory neurons express a variety of voltage-gated Ca2+ channel subtypes, but reports differ on their proportionate representation, and the effects of painful nerve injury on each subtype are not established. We compared levels of high-voltage activated currents in medium-sized (30-40?m) dorsal root ganglion neurons dissociated from control animals and those subjected to spinal nerve ligation, using sequential application of semiselective channel blockers (nisoldipine for L-type, SNX-111 or ?-conotoxin GVIA for N-type, agatoxin IVA or ?-Conotoxin MVIIC for P/Q-type, and SNX-482 for a component of R-type) during either square wave depolarizations or action potential waveform voltage commands. Using sequential administration of multiple blockers, proportions of total Ca2+ current attributable to different subtypes and the effect of injury depended on the sequence of blocker administration and type of depolarization command. Overall, however, N-type and L-type currents comprised the dominant components of ICa in sensory neurons under control conditions, and these subtypes showed the greatest loss of current following injury (L-type 26-71% loss, N-type 0-51% loss). Further exploration of N-type current identified by its sensitivity to ?-conotoxin GVIA applied alone showed that injury reduced the peak N-type current during step depolarization by 68% and decreased the total charge entry during action potential waveform stimulation by 44%. Isolation of N-type current by blockade of all other subtypes demonstrated a 50% loss with injury, and also revealed an injury-related rightward shift in the activation curve. Nonstationary noise analyses of N-type current in injured neurons revealed unitary channel current and number of channels that were not different from control, which indicates that injury-induced loss of current is due to a decrease in channel open probability. Our findings suggest that diminished Ca2+ influx through N-type and L-type channels may contribute to sensory neuron dysfunction and pain after nerve injury. PMID:21277351

McCallum, J. Bruce; Wu, Hsiang-En; Tang, Qingbo; Kwok, Wai-Meng; Hogan, Quinn H.

2011-01-01

95

Caspase-2 Is Upregulated after Sciatic Nerve Transection and Its Inhibition Protects Dorsal Root Ganglion Neurons from Apoptosis after Serum Withdrawal  

PubMed Central

Sciatic nerve (SN) transection-induced apoptosis of dorsal root ganglion neurons (DRGN) is one factor determining the efficacy of peripheral axonal regeneration and the return of sensation. Here, we tested the hypothesis that caspase-2 (CASP2) orchestrates apoptosis of axotomised DRGN both in vivo and in vitro by disrupting the local neurotrophic supply to DRGN. We observed significantly elevated levels of cleaved CASP2 (C-CASP2), compared to cleaved caspase-3 (C-CASP3), within TUNEL+DRGN and DRG glia (satellite and Schwann cells) after SN transection. A serum withdrawal cell culture model, which induced 40% apoptotic death in DRGN and 60% in glia, was used to model DRGN loss after neurotrophic factor withdrawal. Elevated C-CASP2 and TUNEL were observed in both DRGN and DRG glia, with C-CASP2 localisation shifting from the cytosol to the nucleus, a required step for induction of direct CASP2-mediated apoptosis. Furthermore, siRNA-mediated downregulation of CASP2 protected 50% of DRGN from apoptosis after serum withdrawal, while downregulation of CASP3 had no effect on DRGN or DRG glia survival. We conclude that CASP2 orchestrates the death of SN-axotomised DRGN directly and also indirectly through loss of DRG glia and their local neurotrophic factor support. Accordingly, inhibiting CASP2 expression is a potential therapy for improving both the SN regeneration response and peripheral sensory recovery. PMID:23451279

Vigneswara, Vasanthy; Berry, Martin

2013-01-01

96

Evaluation of Behavior and Expression of Receptor Activator of Nuclear Factor-Kappa B Ligand in Dorsal Root Ganglia after Sciatic Nerve Compression and Application of Nucleus Pulposus in Rats  

PubMed Central

Study Design Experimental animal study. Purpose To evaluate pain-related behavior and changes in nuclear factor-kappa B (NF-kB), receptor activator of NF-kB (RANK), and ligand (RANKL) in dorsal root ganglia (DRG) after combined sciatic nerve compression and nucleus pulposus (NP) application in rats. Overview of Literature The pathological mechanisms underlying pain from lumbar-disc herniation have not been fully elucidated. RANKL are transcriptional regulators of inflammatory cytokines. Our aim was to evaluate pain-related behavior and RANKL expression in DRG after sciatic-nerve compression and application of NP in rats. Methods Mechanical hyperalgesia and RANKL expression were assessed in three groups of rats: NP+sciatic nerve compression (2 seconds), sham-operated, and controls (n=20 each). Mechanical hyperalgesia was measured every other day for 3 weeks using von Frey filaments. RANKL expression in L5 DRGs was examined at five and ten days after surgery using immunohistochemistry. Results Mechanical hyperalgesia was observed over the 12-day observation period in the NP+nerve compression group, but not in the control and sham-operated animal groups (p<0.05). RANKL immunoreactivity was seen in the nuclei of L5 DRG neurons, and its expression was significantly upregulated in NP+nerve compression rats compared with control and sham-operated rats (p<0.01). Conclusions The exposure of sciatic nerves to mechanical compression and NP produces pain-related behavior and up-regulation of RANKL in DRG neurons. RANKL may play an important role in mediating pain after sciatic nerve injury with exposure to NP.

Matsuyama, Yoshiyuki; Sakuma, Yoshihiro; Suzuki, Miyako; Orita, Sumihisa; Yamauchi, Kazuyo; Inoue, Gen; Aoki, Yasuchika; Ishikawa, Tetsuhiro; Miyagi, Masayuki; Kamoda, Hiroto; Kubota, Gou; Oikawa, Yasuhiro; Inage, Kazuhide; Sainoh, Takeshi; Sato, Jun; Nakamura, Junichi; Toyone, Tomoaki; Takahashi, Kazuhisa

2014-01-01

97

Bilateral changes of TNF-? and IL10 protein in the lumbar and cervical dorsal root ganglia following a unilateral chronic constriction injury of the sciatic nerve  

Microsoft Academic Search

BACKGROUND: There is a growing body of evidence that unilateral nerve injury induces bilateral response, the mechanism of which is not exactly known. Because cytokines act as crucial signaling molecules for response of peripheral nerves to injury, they may be induced to mediate the reaction in remote structures. METHODS: We studied levels of tumor necrosis factor ? (TNF-?) and interleukin

Radim Jan?álek; Petr Dubový; Ivana Svíženská; Ilona Klusáková

2010-01-01

98

Nerve biopsy  

MedlinePLUS

Biopsy - nerve ... A nerve biopsy is most often done on a nerve in the ankle, forearm, or along a rib. The health care ... feel a prick and a mild sting. The biopsy site will be sore for a few days ...

99

Live-Donor Nerve Transplantation  

Microsoft Academic Search

We recently reported the first case of live-donor nerve transplantation, performed in November 2000 in an 8-month-old infant\\u000a with global obstetric brachial plexus palsy (OBPP) and four root avulsion who had undergone prior sural nerve autografting\\u000a at 3 months. Cross-chest C7 nerve transfer and temporary tacrolimus (TCL)\\/prednisone immunosuppression were utilized. The\\u000a purpose of this chapter is twofold. First, we provide

Scott A. Gruber; Pedro Mancias

100

Upregulation of Dorsal Root Ganglion a2d Calcium Channel Subunit and Its Correlation with Allodynia in Spinal Nerve-Injured Rats  

Microsoft Academic Search

Peripheral nerve injury can lead to a persistent neuropathic pain state in which innocuous tactile stimulation elicits pain behavior (tactile allodynia). Spinal administration of the anticonvulsant gabapentin suppresses allodynia by an unknown mechanism. In vitro studies indicate that gabapentin binds to the a2d-1 (hereafter referred to as a2d) subunit of voltage-gated calcium channels. We hypothesized that nerve injury may result

Z. David Luo; Sandra R. Chaplan; Emiliano S. Higuera; Linda S. Sorkin; Kenneth A. Stauderman; Mark E. Williams; Tony L. Yaksh

2001-01-01

101

Differential regulation of immune responses and macrophage\\/neuron interactions in the dorsal root ganglion in young and adult rats following nerve injury  

Microsoft Academic Search

BACKGROUND: Neuropathic pain is an apparently spontaneous experience triggered by abnormal physiology of the peripheral or central nervous system, which evolves with time. Neuropathic pain arising from peripheral nerve injury is characterized by a combination of spontaneous pain, hyperalgesia and allodynia. There is no evidence of this type of pain in human infants or rat pups; brachial plexus avulsion, which

David Vega-Avelaira; Sandrine M Géranton; Maria Fitzgerald

2009-01-01

102

Nerve conduits for nerve reconstruction  

Microsoft Academic Search

Although autogenous nerve grafting remains the gold standard for repair of peripheral nerve defects, the use of various conduits can be a substitute provided these conduits meet the above-mentioned prerequisites. For the moment, autogenous vein grafts or denatured muscle grafts can be used to bridge short defects, especially in distal sensory nerves. Incorporation of muscle into a vein graft expands

Huan Wang; William C. Lineaweaver

2002-01-01

103

Expression of gamma-aminobutyric acid type A receptor ?2 subunit in the dorsal root ganglion of rats with sciatic nerve injury?  

PubMed Central

The ?-aminobutyric acid neurotransmitter in the spinal cord dorsal horn plays an important role in pain modulation through primary afferent-mediated presynaptic inhibition. The weakening of ?-aminobutyric acid-mediated presynaptic inhibition may be an important cause of neuropathic pain. ?-aminobutyric acid-mediated presynaptic inhibition is related to the current strength of ?-aminobutyric acid A receptor activation. In view of this, the whole-cell patch-clamp technique was used here to record the change in muscimol activated current of dorsal root ganglion neurons in a chronic constriction injury model. Results found that damage in rat dorsal root ganglion neurons following application of muscimol caused concentration-dependent activation of current, and compared with the sham group, its current strength and ?-aminobutyric acid A receptor protein expression decreased. Immunofluorescence revealed that ?-aminobutyric acid type A receptor ?2 subunit protein expression decreased and was most obvious at 12 and 15 days after modeling. Our experimental findings confirmed that the ?-aminobutyric acid type A receptor ?2 subunit in the chronic constriction injury model rat dorsal root ganglion was downregulated, which may be one of the reasons for the reduction of injury in dorsal root ganglion neurons following muscimol-activated currents. PMID:25337100

Lian, Yu; Wang, Yang; Ma, Ketao; Zhao, Lei; Zhang, Zhongshuang; Shang, Yuanyuan; Si, Junqiang; Li, Li

2012-01-01

104

Nerve transfer in brachial plexus traction injuries.  

PubMed

Brachial plexus palsy due to traction injury, especially spinal nerve-root avulsion, represents a severe handicap for the patient. Despite recent progress in diagnosis and microsurgical repair, the prognosis in such cases remains unfavorable. Nerve transfer is the only possibility for repair in cases of spinal nerve-root avulsion. This technique was analyzed in 37 patients with 64 reinnervation procedures of the musculocutaneous and/or axillary nerve using upper intercostal, spinal accessory, and regional nerves as donors. The most favorable results, with an 83.8% overall rate of useful functional recovery, were obtained in patients with upper brachial plexus palsy in which regional donor nerves, such as the medial pectoral, thoracodorsal, long thoracic, and subscapular nerves, had been used. The overall rates of recovery for the spinal accessory and upper intercostal nerves were 64.3% and 55.5%, respectively, which are significantly lower. The authors evaluate the results of nerve transfer and analyze different donor nerves as factors influencing the prognosis of surgical repair. PMID:1730947

Samardzic, M; Grujicic, D; Antunovic, V

1992-02-01

105

Single-dose application of CNTF and BDNF improves remyelination of regenerating nerve fibers after C7 ventral root avulsion and replantation.  

PubMed

Although axonal regeneration has been observed after replantation of avulsed ventral roots (VR) into the spinal cord, the functional outcome of this treatment in terms of motor reinnervation is unsatisfactory. In the present study, effects of single-dose ciliary and/or brain-derived neurotrophic factor (CNTF, BDNF) application on axon regeneration after C7 VR avulsion and replantation in adult rabbits were morphologically assessed by analysis of numbers, calibers, and myelination of axons in replanted VRs. Electromyography (EMG) was carried out to document the time course of de- and reinnervation in individual animals. After 3 weeks, replanted C7 VRs were almost devoid of myelinated axons. At week 8, active EMG-denervation was confirmed in affected muscles, but was less pronounced in neurotrophic factor (NF)-treated animals than in controls. Reinnervation potentials were identified in paraspinal muscles in more NF-treated animals than in controls. After 6 months, the number of myelinated axons in replanted VRs was approximately 45% of that in unlesioned roots in all groups, with small-sized axons constituting the majority of axons. At this time, more NF-treated animals than controls featured reinnervation. Moreover, myelination deficits of regenerated axons in controls were less pronounced in NF-treated animals. Especially in CNTF + BDNF-treated animals, myelination of regenerated axons of specific sizes was significantly increased compared to regenerated controls. In summary, NFs stimulated reinnervation early after the lesion and, for the first time, our morphological data quantitatively indicate positive effects of CNTF + BDNF on remyelination. PMID:18373486

Lang, Eva M; Schlegel, Nicholas; Reiners, Karlheinz; Hofmann, Gunther O; Sendtner, Michael; Asan, Esther

2008-04-01

106

Peripheral Nerve Disorders  

MedlinePLUS

... spinal cord. Like static on a telephone line, peripheral nerve disorders distort or interrupt the messages between the brain ... body. There are more than 100 kinds of peripheral nerve disorders. They can affect one nerve or many nerves. ...

107

Nanofibrous nerve conduit-enhanced peripheral nerve regeneration.  

PubMed

Fibre structures represent a potential class of materials for the formation of synthetic nerve conduits due to their biomimicking architecture. Although the advantages of fibres in enhancing nerve regeneration have been demonstrated, in vivo evaluation of fibre size effect on nerve regeneration remains limited. In this study, we analyzed the effects of fibre diameter of electrospun conduits on peripheral nerve regeneration across a 15-mm critical defect gap in a rat sciatic nerve injury model. By using an electrospinning technique, fibrous conduits comprised of aligned electrospun poly (?-caprolactone) (PCL) microfibers (981?±?83 nm, Microfiber) or nanofibers (251?±?32 nm, Nanofiber) were obtained. At three months post implantation, axons regenerated across the defect gap in all animals that received fibrous conduits. In contrast, complete nerve regeneration was not observed in the control group that received empty, non-porous PCL film conduits (Film). Nanofiber conduits resulted in significantly higher total number of myelinated axons and thicker myelin sheaths compared to Microfiber and Film conduits. Retrograde labeling revealed a significant increase in number of regenerated dorsal root ganglion sensory neurons in the presence of Nanofiber conduits (1.93 ± 0.71 × 10(3) vs. 0.98 ± 0.30 × 10(3) in Microfiber, p?nerve regeneration. These results could provide useful insights for future nerve guide designs. PMID:22700359

Jiang, Xu; Mi, Ruifa; Hoke, Ahmet; Chew, Sing Yian

2014-05-01

108

Morphological differences in skeletal muscle atrophy of rats with motor nerve and/or sensory nerve injury?  

PubMed Central

Skeletal muscle atrophy occurs after denervation. The present study dissected the rat left ventral root and dorsal root at L4-6 or the sciatic nerve to establish a model of simple motor nerve injury, sensory nerve injury or mixed nerve injury. Results showed that with prolonged denervation time, rats with simple motor nerve injury, sensory nerve injury or mixed nerve injury exhibited abnormal behavior, reduced wet weight of the left gastrocnemius muscle, decreased diameter and cross-sectional area and altered ultrastructure of muscle cells, as well as decreased cross-sectional area and increased gray scale of the gastrocnemius muscle motor end plate. Moreover, at the same time point, the pathological changes were most severe in mixed nerve injury, followed by simple motor nerve injury, and the changes in simple sensory nerve injury were the mildest. These findings indicate that normal skeletal muscle morphology is maintained by intact innervation. Motor nerve injury resulted in larger damage to skeletal muscle and more severe atrophy than sensory nerve injury. Thus, reconstruction of motor nerves should be considered first in the clinical treatment of skeletal muscle atrophy caused by denervation. PMID:25337102

Zhao, Lei; Lv, Guangming; Jiang, Shengyang; Yan, Zhiqiang; Sun, Junming; Wang, Ling; Jiang, Donglin

2012-01-01

109

Nerve Racking  

NSDL National Science Digital Library

This lesson describes the function and components of the human nervous system. It helps students understand the purpose of our brain, spinal cord, nerves and the five senses. How the nervous system is affected during spaceflight is also discussed in this lesson.

Integrated Teaching And Learning Program

110

Computer Simulation of Antidromic Facial Nerve Response Waveform  

Microsoft Academic Search

Conclusion: An assessment of facial nerve (FN) damage on the basis of antidromic facial nerve response (AFNR) was established by computer simulation analysis. Computer simulation has the advantage of being able to assume any type of lesion. In the near future, computer analysis should provide another experimental method which displaces animal experiments, thus circumventing the ethical dilemma associated with animal

Mitsuru Iwai; Taizo Takeda; Hiroaki Nakatani; Akinobu Kakigi

2009-01-01

111

Reinnervation of avulsed brachial plexus using the spinal accessory nerve.  

PubMed

The use of the accessory nerve as a donor is one of the possibilities for the reinnervation of the brachial plexus in cases of paralysis due to root avulsion. In this paper, an analysis of the reinnervation of the musculocutaneous or axillary nerve using the spinal accessory nerve is made on 13 cases, 8 of total and 5 of upper partial avulsion. In all cases, Allieu's technique was used, but in seven cases reinnervation was supplemented by upper intercostal nerves when there was total avulsion and/or by the medial pectoral nerve when there was partial avulsion. The methods are discussed and compared with the intercostobrachial anastomosis. PMID:2154041

Samardzic, M; Grujicic, D; Antunovic, V; Joksimovic, M

1990-01-01

112

Modeling root reinforcement using root-failure Weibull survival function  

NASA Astrophysics Data System (ADS)

Root networks contribute to slope stability through complicated interactions that include mechanical compression and tension. Due to the spatial heterogeneity of root distribution and the dynamic of root turnover, the quantification of root reinforcement on steep slope is challenging and consequently the calculation of slope stability as well. Although the considerable advances in root reinforcement modeling, some important aspect remain neglected. In this study we address in particular to the role of root strength variability on the mechanical behaviors of a root bundle. Many factors may contribute to the variability of root mechanical properties even considering a single class of diameter. This work presents a new approach for quantifying root reinforcement that considers the variability of mechanical properties of each root diameter class. Using the data of laboratory tensile tests and field pullout tests, we calibrate the parameters of the Weibull survival function to implement the variability of root strength in a numerical model for the calculation of root reinforcement (RBMw). The results show that, for both laboratory and field datasets, the parameters of the Weibull distribution may be considered constant with the exponent equal to 2 and the normalized failure displacement equal to 1. Moreover, the results show that the variability of root strength in each root diameter class has a major influence on the behavior of a root bundle with important implications when considering different approaches in slope stability calculation. Sensitivity analysis shows that the calibration of the tensile force and the elasticity of the roots are the most important equations, as well as the root distribution. The new model allows the characterization of root reinforcement in terms of maximum pullout force, stiffness, and energy. Moreover, it simplifies the implementation of root reinforcement in slope stability models. The realistic quantification of root reinforcement for tensile, shear and compression behavior allows the consideration of the stabilization effects of root networks on steep slopes and the influence that this has on the triggering of shallow landslides.

Schwarz, M.; Giadrossich, F.; Cohen, D.

2013-03-01

113

Cavernous nerve regeneration using acellular nerve grafts  

Microsoft Academic Search

Introduction  The restoration of erectile function following complete transection of nerve tissue during surgery remains challenging. Recently,\\u000a graft procedures using sural nerve grafts during radical prostatectomy have had favorable outcomes, and this has rekindled\\u000a interest in the applications of neural repair in a urologic setting. Although nerve repair using autologous donor graft is\\u000a the gold standard of treatment currently, donor nerve

Stephen S. Connolly; James J. Yoo; Mohamed Abouheba; Shay Soker; W. Scott McDougal; Anthony Atala

2008-01-01

114

Soil-root mechanical interactions within bundles of roots  

NASA Astrophysics Data System (ADS)

Root-soil mechanical interactions play an important role in strength and force redistribution in rooted soil. Recent advances in root reinforcement modeling implement detailed representation of root geometry and mechanical properties as well as root-soil mechanical interactions. Nevertheless, root-soil mechanical interactions are often considered at the single root scale ignoring interactions between neighboring roots and root bundles known to play important role in similar applications such as engineered composite material reinforcement. The objective was to quantify mechanical interactions among neighboring roots or roots network using pullout laboratory experiments and modeling. We focus on the on effects of such interactions on global pull out force of a bundle of roots via better understanding of transmission of radial stresses to soil matrix due to the friction at the interface soil-root. Additionally, we wish to predict how cumulative friction changes along a single root axis with and without branching points during the slipping out. Analytical models of fiber reinforced materials show the magnitude of bonded friction depends on three key parameters: bond modulus, maximal bond strength and difference between the Young moduli of fiber and Young moduli of matrix. Debonded friction is calculated assuming failure follows Coulomb failure that includes apparent cohesion, effective normal stress and residual root soil friction angle. We used a pullout device to measure displacement and force of individual roots and for the bundle of roots. Additionally, we monitored and detected activation of root-soil friction by six acoustic emission sensors placed on waveguide in contact with the soil matrix. Results from experiments with parallel and crossing roots demonstrated the importance of considering factors such as distance of root axis, branching points, crossing of roots and roots diameter for the behavior of bundle of roots and inclined roots during pullout. Acoustic emission measurements provided interesting insights into progressive activation of root-soil friction. These results enhance understanding of root reinforcement mechanism and enable more realistic implementation of root reinforcement modeling for stability calculation of vegetated slopes.

Giadrossich, Filippo; Schwarz, Massimiliano; Preti, Federico; Or, Dani

2010-05-01

115

The Cranial Nerves of the Senegal Bichir, Polypterus senegalus [Osteichthyes: Actinopterygii: Cladistia]; pp. 55–66  

Microsoft Academic Search

The organization of the roots, ganglia and peripheral distribution of the rami of the cranial nerves of larval and juvenile Senegal bichirs was examined with a wide range of techniques, including gross dissection and histological preparations. The profundal nerve of bichirs is completely separate from the trigeminal nerve and innervates the skin overlying the orbit and snout, and there is

Tatjana Piotrowski; R. Glenn Northcutt

1996-01-01

116

Diffuse spinal and intercostal nerve involvement in chronic inflammatory demyelinating polyradiculoneuropathy: MRI findings  

Microsoft Academic Search

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an uncommon demyelinating disorder with a relapsing and remitting or continuously progressive course. Hypertrophic nerve roots, sometimes associated with gadolinium enhancement, has been reported more commonly in lumbar spine and less commonly in the brachial plexus and cervical roots; however, diffuse involvement of intercostal nerves bilaterally has never been reported previously. We present MRI

Berna Oguz; Kader Karli Oguz; Aysenur Cila; Ersin Tan

2003-01-01

117

A Mechanical Model of Neural Tissue Displacement During Lorentz Effect Imaging  

PubMed Central

Song and co-workers recently proposed a method for MRI detection of biocurrents in nerves called “Lorentz Effect Imaging”. When exposed to a magnetic field, neural currents are subjected to a Lorentz force that moves the nerve. If the displacement is large enough, an artifact is predicted in the MR signal. In this paper, the displacement of a nerve of radius a in a surrounding tissue of radius b and shear modulus µ is analyzed. The nerve carries a current density J and lies in a magnetic field B. The solution to the resulting elasticity problem indicates that the nerve moves a distance BJ4?a2ln(ba). Using realistic parameters for a human median nerve in a 4 T field, this calculated displacement is 0.013 µm or less. The distribution of displacement is widespread throughout the tissue, and is not localized near the nerve. This displacement is orders of magnitude too small to be observed by conventional MRI methods. PMID:19097218

Roth, Bradley J.; Basser, Peter J.

2009-01-01

118

Precision displacement reference system  

DOEpatents

A precision displacement reference system is described, which enables real time accountability over the applied displacement feedback system to precision machine tools, positioning mechanisms, motion devices, and related operations. As independent measurements of tool location is taken by a displacement feedback system, a rotating reference disk compares feedback counts with performed motion. These measurements are compared to characterize and analyze real time mechanical and control performance during operation.

Bieg, Lothar F. (Albuquerque, NM); Dubois, Robert R. (Albuquerque, NM); Strother, Jerry D. (Edgewood, NM)

2000-02-22

119

Nerve injuries about the elbow in the athlete.  

PubMed

The athlete's elbow is a remarkable example of motion, strength, and durability. The stress placed on the elbow during sport, including the throwing motion, may lead to soft-tissue ligamentous and nerve injury. The thrower's elbow illustrates one example of possible nerve injury about the elbow in sport, related to chronic repetitive tensile and compressive stresses to the ulnar nerve associated with elbow flexion and valgus position. Besides the throwing athlete, nerve injury from high-energy direct-impact forces may also damage nerves around the elbow in contact sports. Detailed history and physical examination can often make the diagnosis of most upper extremity neuropathies. The clinician must be aware of the possibility of isolated or combined nerve injury as far proximal as the cervical nerve roots, through the brachial plexus, to the peripheral nerve terminal branches. Electrodiagnostic studies are occasionally beneficial for diagnosis with certain nerves. Nonoperative management is often successful in most elbow and upper extremity neuropathies. If conservative treatment fails, then surgical treatment should address all potentially offending structures. In the presence of medial laxity and concurrent ulnar neuritis, the medial ulnar collateral ligament warrants surgical treatment, in addition to transposition of the ulnar nerve. The morbidity of open surgical decompression of nerves in and around the elbow is potentially career threatening in the throwing athlete. This mandates an assessment of the adequacy of the nonsurgical treatment and a thorough preoperative discussion of the risks and benefits of surgery. PMID:25077754

Harris, Joshua D; Lintner, David M

2014-09-01

120

Peripheral Nerve Regeneration by Artificial Nerve Guides  

Microsoft Academic Search

It is more than 20 years since artificial nerve guides (or conduits) were introduced into clinical practice as a reliable\\u000a alternative to autograft. They are basically cylindrical conduits inside which a regenerating nerve stump may find protection\\u000a and guidance. Early guides were made of silicone and were not biodegradable; they were shown to support nerve regeneration\\u000a but, subsequently, were considered

A. Merolli; L. Rocchi

121

Spinal Cord Metastasis of a Non-neurofibromatosis Type1 Malignant Peripheral Nerve Sheath Tumor: An Unusual Manifestation of a Rare Tumor  

Microsoft Academic Search

Summary Malignant peripheral nerve sheath tumors are rare spindle-cell sarcomas derived from Schwann cells or pluripotent cells of the neural crest. They arise from the spinal roots, peripheral nerves, brachial and lumbosacral plexi, cranial nerves and terminal nerve fibers within soft tissue, intestine, lung and bone. These tumors recur either locally, or metastasize distally. Most of these tumors occur in

William S. Baek; Peter Pytel; Samir D. Undevia; Helene Rubeiz

2005-01-01

122

Optic Nerve Imaging  

MedlinePLUS

... Tomography (OCT) , which measures the reflection of laser light much like an ultrasound measures the reflection of sound, can directly measure the thickness of the nerve fiber layer and create a three dimensional representation of the optic nerve. ...

123

Engineering Peripheral Nerve Repair  

PubMed Central

Current approaches for treating peripheral nerve injury have resulted in promising, yet insufficient functional recovery compared to the clinical standard of care, autologous nerve grafts. In order to design a construct that can match the regenerative potential of the autograft, all facets of nerve tissue must be incorporated in a combinatorial therapy. Engineered biomaterial scaffolds in the future will have to promote enhanced regeneration and appropriate reinnervation by targeting the highly sensitive response of regenerating nerves to their surrounding microenvironment. PMID:23790730

Marquardt, Laura; Sakiyama-Elbert, Shelly E.

2013-01-01

124

Chromo-fluorogenic BODIPY-complexes for selective detection of V-type nerve agent surrogates.  

PubMed

Two new Eu(3+) and Au(3+) BODIPY-complexes capable of chromo-fluorogenically detecting micromolar concentrations of V-type nerve agent surrogates by a simple displacement assay are described. PMID:25233370

Barba-Bon, Andrea; Costero, Ana María; Gil, Salvador; Sancenón, Félix; Martínez-Máñez, Ramón

2014-11-11

125

Axonal regeneration of sensory nerves is delayed by continuous intrathecal infusion of nerve growth factor.  

PubMed

While it is well established that nerve growth factor is growth promoting for sensory neurons in culture, it is unclear whether it serves such a function in vivo. In fact, our previous studies led to the hypothesis that nerve growth factor could actually impair axonal regeneration by reducing the neuronal cell body response to injury. In the present study, the consequence of continuous intrathecal infusion of nerve growth factor on regeneration of sensory neurons was examined in rats given a bilateral sciatic nerve crush. Rats received nerve growth factor (125 ng/h) as a continuous infusion into the subarachnoid space of the lumbar spinal cord via an osmotic minipump (Alzet); controls received cytochrome C. At seven or 10 days, the pump was removed and L4 or L5 dorsal root ganglion exposed and injected with 50 microCi of (3H)leucine. Animals were killed 24 h later, the sciatic nerves removed, cut into 3 mm segments and the radioactivity in each segment determined by liquid scintillation spectrophotometry. Maximal regeneration distances (determined from the front of the resultant transport curves) were similarly reduced (by approximately 6 mm) in nerve growth factor-infused compared to cytochrome C-infused rats. Thus, regeneration rates (determined between eight and 11 days) were unaltered by nerve growth factor infusion; regeneration rates from cytochrome C-infused and nerve growth factor-infused animals were 2.8 mm/day and 3.1 mm/day, respectively. However, nerve growth factor significantly (P < 0.005) increased the delay to onset for regeneration by two days. Taken together, the present study demonstrates that nerve growth factor delays the onset of regeneration without affecting the rate of regeneration. The results implicate the involvement of at least two signals in the regulation of axonal regeneration in dorsal root ganglion neurons. It is suggested that the loss of nerve growth factor serves as an early, induction signal regulating the onset of regeneration and that a second, unidentified signal independently serves to maintain regeneration. PMID:9027875

Gold, B G

1997-02-01

126

Surgical anatomy of the pudendal nerve and its clinical implications.  

PubMed

A study of the surgical anatomy of the pudendal nerve (PN) was performed in 13 female and 7 male cadavers. The knowledge of the precise anatomy and anomalies of this important nerve would help in better localization of the nerve and its roots and branches for neurostimulation or for pudendal canal decompression in pudendal canal syndrome. Two routes were used in the dissection: gluteal and perineal. The PN was identified and its course was followed from its roots to its termination. The PN was composed of three roots derived from the 2nd, 3rd, and 4th anterior sacral rami (S 2,3,4). The roots received a contribution from S 1 in five cadavers and from S 5 in one. The three roots formed two cords. The first root continued as the upper cord while the second and third root fused together producing the lower cord. The PN was formed by union of the two cords a short distance proximal to the sacrospinous ligament, and then crossed the back of the ligament. In no specimen did the nerve cross the ischial spine. The inferior rectal nerve arose from the PN in the pudendal canal in 18 cadavers. In two cases it came out proximal to the canal; this would spare the two subjects the anorectal manifestations of the pudendal canal syndrome. As the PN crossed the back of the sacrospinous ligament, it gave origin to a branch that supplied the levator ani muscle. This branch was only found in male cadavers and we call it "accessory rectal nerve"; the levator ani muscle in such cadavers was doubly innervated on its perineal aspect. PMID:7712320

Shafik, A; el-Sherif, M; Youssef, A; Olfat, E S

1995-01-01

127

Optic nerve trauma.  

PubMed

Trauma to the optic nerve may be direct, such as from a penetrating object, or indirect, which may result despite lack of direct contact of an object with the nerve. Although indirect injury initially causes no change in the appearance of the nerve head, within a matter of weeks optic atrophy will be manifest. The pathophysiology of nerve damage is incompletely understood. Management is controversial; steroid therapy has been advocated, as has surgical decompression of the nerve. Indirect injuries affecting the optic nerve may also result from torsional rotation of the globe (avulsion) and from subdural or subarachnoid hemorrhage (Terson's syndrome). There is no treatment for optic nerve avulsion; the unaffected eye should be protected with appropriate eyewear. Hemorrhaging in the retina and vitreous in Terson's syndrome should be monitored for resolution and risk of retinal detachment. Computed tomography may be necessary if subarachnoid or intracranial hemorrhages are suspected. PMID:8268699

Dul, M W

1993-01-01

128

Optical displacement sensor  

DOEpatents

An optical displacement sensor is disclosed which uses a vertical-cavity surface-emitting laser (VCSEL) coupled to an optical cavity formed by a moveable membrane and an output mirror of the VCSEL. This arrangement renders the lasing characteristics of the VCSEL sensitive to any movement of the membrane produced by sound, vibrations, pressure changes, acceleration, etc. Some embodiments of the optical displacement sensor can further include a light-reflective diffractive lens located on the membrane or adjacent to the VCSEL to control the amount of lasing light coupled back into the VCSEL. A photodetector detects a portion of the lasing light from the VCSEL to provide an electrical output signal for the optical displacement sensor which varies with the movement of the membrane.

Carr, Dustin W. (Albuquerque, NM)

2008-04-08

129

Water displacement mercury pump  

DOEpatents

A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

Nielsen, M.G.

1984-04-20

130

Water displacement mercury pump  

DOEpatents

A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

Nielsen, Marshall G. (Woodside, CA)

1985-01-01

131

Root hairs.  

PubMed

Roots hairs are cylindrical extensions of root epidermal cells that are important for acquisition of nutrients, microbe interactions, and plant anchorage. The molecular mechanisms involved in the specification, differentiation, and physiology of root hairs in Arabidopsis are reviewed here. Root hair specification in Arabidopsis is determined by position-dependent signaling and molecular feedback loops causing differential accumulation of a WD-bHLH-Myb transcriptional complex. The initiation of root hairs is dependent on the RHD6 bHLH gene family and auxin to define the site of outgrowth. Root hair elongation relies on polarized cell expansion at the growing tip, which involves multiple integrated processes including cell secretion, endomembrane trafficking, cytoskeletal organization, and cell wall modifications. The study of root hair biology in Arabidopsis has provided a model cell type for insights into many aspects of plant development and cell biology. PMID:24982600

Grierson, Claire; Nielsen, Erik; Ketelaarc, Tijs; Schiefelbein, John

2014-01-01

132

Patterns of slow transport in sensory nerves  

Microsoft Academic Search

An examination of the pattern of outflow of radioactivity in sciatic nerves was made at times from 1 to 82 days in the rat and up to 132 days in the cat after injecting the L5 and L7 dorsal root ganglia, respectively, with 3H-leucine. Slow waves moving at a rate of 1-2 mm\\/day were looked for on the basis of

D. P. Stromska; S. Ochs

1981-01-01

133

Displaced Homemakers: Unresolved Issues.  

ERIC Educational Resources Information Center

Problems of today's displaced homemakers overlap with those of women in the 1960s. Problems of women seeking employment are similar to those of minority groups, older workers and welfare recipients. Recent legislation has expanded to fulfill some of the needs of women returning to the labor force. (Author/BEF)

Zawada, Mary Ann

1980-01-01

134

Control rod displacement  

Microsoft Academic Search

This patent describes a nuclear reactor including a core, cylindrical control rods, a single support means supporting the control rods from their upper ends in spaced apart positions and movable for displacing the control rods in their longitudinal direction between a first end position in which the control rods are fully inserted into the core and a second end position

Nakazato

1987-01-01

135

A malignant peripheral nerve-sheath tumour responding to chemotherapy.  

PubMed

A malignant peripheral nerve-sheath tumour developed in the right S1 nerve root in a man aged 30 causing back pain and sciatica. CT and MRI revealed a destructive tumour of the sacrum invading the retroperitoneal space. The tumour was not resectable with an adequate margin. Chemotherapy, consisting of high-dose ifosfamide followed by a combination of vincristine, doxorubicin and cyclophosphamide, was given with success. Malignant peripheral nerve-sheath tumours are thought to respond weakly to chemotherapy, but the response in our patient was complete. PMID:14765877

Masui, F; Yokoyama, R; Soshi, S; Beppu, Y; Asanuma, K; Fujii, K

2004-01-01

136

The Furcal Nerve Revisited  

PubMed Central

Atypical sciatica and discrepancy between clinical presentation and imaging findings is a dilemma for treating surgeon in management of lumbar disc herniation. It also constitutes ground for failed back surgery and potential litigations thereof. Furcal nerve (Furcal = forked) is an independent nerve with its own ventral and dorsal branches (rootlets) and forms a link nerve that connects lumbar and sacral plexus. Its fibers branch out to be part of femoral and obturator nerves in-addition to the lumbosacral trunk. It is most commonly found at L4 level and is the most common cause of atypical presentation of radiculopathy/sciatica. Very little is published about the furcal nerve and many are unaware of its existence. This article summarizes all the existing evidence about furcal nerve in English literature in an attempt to create awareness and offer insight about this unique entity to fellow colleagues/professionals involved in spine care.

Dabke, Harshad V.

2014-01-01

137

Peripheral nerve regeneration and neurotrophic factors  

PubMed Central

The role of neurotrophic factors in the maintenance and survival of peripheral neuronal cells has been the subject of numerous studies. Administration of exogenous neurotrophic factors after nerve injury has been shown to mimic the effect of target organ-derived trophic factors on neuronal cells. After axotomy and during peripheral nerve regeneration, the neurotrophins NGF, NT-3 and BDNF show a well defined and selective beneficial effect on the survival and phenotypic expression of primary sensory neurons in dorsal root ganglia and of motoneurons in spinal cord. Other neurotrophic factors such as CNTF, GDNF and LIF also exert a variety of actions on neuronal cells, which appear to overlap and complement those of the neurotrophins. In addition, there is an indirect contribution of GGF to nerve regeneration. GGF is produced by neurons and stimulates proliferation of Schwann cells, underlining the close interaction between neuronal and glial cells during peripheral nerve regeneration. Different possibilities have been investigated for the delivery of growth factors to the injured neurons, in search of a suitable system for clinical applications. The studies reviewed in this article show the therapeutic potential of neurotrophic factors for the treatment of peripheral nerve injury and for neuropathies. PMID:10227662

TERENGHI, GIORGIO

1999-01-01

138

Optical stimulation of peripheral nerves in vivo  

NASA Astrophysics Data System (ADS)

This dissertation documents the emergence and validation of a new clinical tool that bridges the fields of biomedical optics and neuroscience. The research herein describes an innovative method for direct neurostimulation with pulsed infrared laser light. Safety and effectiveness of this technique are first demonstrated through functional stimulation of the rat sciatic nerve in vivo. The Holmium:YAG laser (lambda = 2.12 mum) is shown to operate at an optimal wavelength for peripheral nerve stimulation with advantages over standard electrical neural stimulation; including contact-free stimulation, high spatial selectivity, and lack of a stimulation artifact. The underlying biophysical mechanism responsible for transient optical nerve stimulation appears to be a small, absorption driven thermal gradient sustained at the axonal layer of nerve. Results explicitly prove that low frequency optical stimulation can reliably stimulate without resulting in tissue thermal damage. Based on the positive results from animal studies, these optimal laser parameters were utilized to move this research into the clinic with a combined safety and efficacy study in human subjects undergoing selective dorsal rhizotomy. The clinical Holmium:YAG laser was used to effectively stimulate human dorsal spinal roots and elicit functional muscle responses recorded during surgery without evidence of nerve damage. Overall these results predict that this technology can be a valuable clinical tool in various neurosurgical applications.

Wells, Jonathon D.

139

Nerve and Blood Vessels  

Microsoft Academic Search

From the histologic point of view, nerves are round or flattened cords, with a complex internal structure made of myelinated\\u000a and unmyelinated nerve fibers, containing axons and Schwann cells grouped in fascicles (Fig. 4.1a) (Erickson 1997). Along the course of the nerve, fibers can traverse from one fascicle to another and fascicles can split and merge. Based\\u000a on the fascicular

Maura Valle; Maria Pia Zamorani

140

Major peripheral nerve injuries.  

PubMed

Major peripheral nerve injuries in the upper extremities can result in significant morbidity. Understanding the pathophysiology of these injuries aids in the assessment and planning of appropriate treatment. With limited nerve mobilization, tension-free repairs can often be performed using sutures, fibrin glue, or nerve connectors. Acellular allograft and autograft reconstruction are better for bridging any gaps greater than a few millimeters. Adherence to proper principles of nerve repair improves the chances of achieving a favorable result, although in general these injuries portend a guarded prognosis. PMID:23895717

Isaacs, Jonathan

2013-08-01

141

Displacement and Velocity Ratios  

NSDL National Science Digital Library

This interactive presentation, created by James Bourassa and John Rosz for the Electromechanical Digital Library, discusses displacement and velocity ratios. Bourassa and Rosz begin by providing detailed definitions of both topics and then provide mathematical examples of each. Once this basic explanation is complete, the authors allow students to practice these theories in a set of self-correcting quiz questions. Bourassa and Rosz explain each using helpful interactive flash animations. These are not only useful in explanation, but they allow the student to more fully engage with the topic. Overall, this is a nice introduction to the physical and mathematical concepts of displacement and velocity ratios. This could be a valuable learning resource in everything from a physics to a technical education classroom.

Bourassa, James; Rosz, John

2011-04-05

142

The Displaced Aggression Questionnaire  

Microsoft Academic Search

Previous measures of aggressive personality have focused on direct aggression (i.e., retaliation toward the provoking agent). An original self-report measure of trait displaced aggression is presented. Exploratory and confirmatory factor analyses provided support for a 3-factor conceptualization of the construct. These analyses identified an affective dimension (angry rumination), a cognitive dimension (revenge planning), and a behavioral dimension (general tendency to

Thomas F. Denson; William C. Pedersen; Norman Miller

2006-01-01

143

Above Water: Buoyancy & Displacement  

NSDL National Science Digital Library

In an investigation called "Shape It!" learners craft tiny boats out of clay, set them afloat on water and then add weight loads to them, in order to explore: how objects stay afloat in water; what the relationship is among surface tension, buoyancy, density and displacement; and how shape, size, and type of material affect an object's ability to remain buoyant. The introductory text discusses how heavy steel ships can float on bodies of water like rivers, bays and oceans.

Jersey, New; Center, Liberty S.; Coalition, New J.

2006-01-01

144

RTV 21 Displacements  

SciTech Connect

A seal is needed for the cover of the Nitrogen Test Vessel in order to prevent leakage of the N{sub 2} gas. This seal is to be molded out of RTV 21. In this experiment, the Modulus of Elasticity of the RTV was sought after, and the displacements of the RTV due to various stresses were measured to see if they were large enough to provide a tight seal between the vessel and its cover.

Kurita, C.H.; /Fermilab

1987-02-04

145

Survival and regeneration of cutaneous and muscular afferent neurons after peripheral nerve injury in adult rats  

Microsoft Academic Search

Peripheral nerve injury induces the retrograde degeneration of dorsal root ganglion (DRG) cells, which affects predominantly\\u000a the small-diameter cutaneous afferent neurons. This study compares the time-course of retrograde cell death in cutaneous and\\u000a muscular DRG cells after peripheral nerve transection as well as neuronal survival and axonal regeneration after primary repair\\u000a or nerve grafting. For comparison, spinal motoneurons were also

Dag Welin; Liudmila N. Novikova; Mikael Wiberg; Jan-Olof Kellerth; Lev N. Novikov

2008-01-01

146

Development of a malignant peripheral nerve sheath tumor following treatment for testicular seminoma  

Microsoft Academic Search

A novel case is reported in which an S2 nerve root malignant peripheral nerve sheath tumor was diagnosed approximately 8 years after treatment for Stage I testicular seminoma. This patient underwent right orchiectomy and subsequent irradiation therapy to the periaortic region, including the sacrum. Postoperative radiation therapy likely played a role in the development of this second malignancy. UROLOGY 50:

D. A. West; R. O. Parra; A. Manepalli; R. J. Bernardi; J. M. Cummings

1997-01-01

147

Patient-specific factors in the proximity of the inferior alveolar nerve to the tooth apex  

PubMed Central

Objectives: To evaluate whether age and gender differences are predictive factors for inferior alveolar nerve position with respect to mandibular first molar roots. Study Design: Cone-beam computed tomography scans [0.2-mm3 voxel size; n = 200 (100 males, 100 females)] of patients aged 15–65 years showing mandibular first and second molars were included in this study. Patients with pathoses that might affect inferior alveolar nerve position, including second molar and/or first premolar extraction, were excluded. Fourteen measurements (mm) were taken from the inferior alveolar nerve to the mesial and distal root apices. Subjects were grouped by age and gender. Data were analysed using two-way analyses of variance with post hoc Bonferroni corrections. Results: The distance from the inferior alveolar nerve to the root apices was smaller in females than males, regardless of age (p < 0.01). Distal roots were closer to the nerve than mesial roots in both genders (p < 0.05). Total buccolingual mandibular length (at 3-mm apical level) was shorter in females than males (p < 0.01) but mean buccolingual mandibular width at the level of the inferior alveolar canal did not differ. Nerve–root apex distances were significantly shorter in males and females aged 16–25 and 56–65 years than in other age groups (p < 0.01). Conclusions: The distance between inferior alveolar nerve and mandibular first molar roots depends upon the age and gender: it is shorter in females than in males and in subjects aged 16–25 years and >55 years than in other age groups. Key words:Age, cone-beam computed tomography, inferior alveolar nerve, root apex, gender. PMID:22926478

Adiguzel, Ozkan; Kaya, Sadullah; Akkus, Zeki

2012-01-01

148

Modeling root reinforcement using a root-failure Weibull survival function  

NASA Astrophysics Data System (ADS)

Root networks contribute to slope stability through complex interactions with soil that include mechanical compression and tension. Due to the spatial heterogeneity of root distribution and the dynamics of root turnover, the quantification of root reinforcement on steep slopes is challenging and consequently the calculation of slope stability also. Although considerable progress has been made, some important aspects of root mechanics remain neglected. In this study we address specifically the role of root-strength variability on the mechanical behavior of a root bundle. Many factors contribute to the variability of root mechanical properties even within a single class of diameter. This work presents a new approach for quantifying root reinforcement that considers the variability of mechanical properties of each root diameter class. Using the data of laboratory tensile tests and field pullout tests, we calibrate the parameters of the Weibull survival function to implement the variability of root strength in a numerical model for the calculation of root reinforcement (RBMw). The results show that, for both laboratory and field data sets, the parameters of the Weibull distribution may be considered constant with the exponent equal to 2 and the normalized failure displacement equal to 1. Moreover, the results show that the variability of root strength in each root diameter class has a major influence on the behavior of a root bundle with important implications when considering different approaches in slope stability calculation. Sensitivity analysis shows that the calibration of the equations of the tensile force, the elasticity of the roots, and the root distribution are the most important steps. The new model allows the characterization of root reinforcement in terms of maximum pullout force, stiffness, and energy. Moreover, it simplifies the implementation of root reinforcement in slope stability models. The realistic quantification of root reinforcement for tensile, shear and compression behavior allows for the consideration of the stabilization effects of root networks on steep slopes and the influence that this has on the triggering of shallow landslides.

Schwarz, M.; Giadrossich, F.; Cohen, D.

2013-11-01

149

Entrapment of the Fifth Lumbar Spinal Nerve by Advanced Osteophytic Changes of the Lumbosacral Zygapophyseal Joint: A Case Report  

PubMed Central

A 54-year-old female patient had a 6-year history of backache and left sciatica. Five years earlier, she had undergone surgery in another hospital for left L4-5 disc herniation. Computed tomography revealed the ossified wall that enclosed the left L5 nerve root. There were also osteophytic changes in the left L5-S zygapophyseal joint. These osteophytes developed rostrally, along the left L5 nerve root, throug h the intervertebral foramina. We performed decompression surgery for the left L5 nerve root, and surgery resulted in symptomatic relief. We experienced a rare clinical presentation of osteophytic formation, with a specific configuration in relation to the nerve root. Surgeons should be aware of entrapment of the lumbar spinal nerve by advanced osteophytic changes occurring in the zygapophyseal joint after lumbar surgery. PMID:23275815

Yuguchi, Takamichi; Iwatsuki, Koichi; Yoshimine, Toshiki

2012-01-01

150

Displacement cascades in polyatomic materials  

SciTech Connect

Using a continuous-slowing-down, random amorphous material model, we have studied displacement cascades in a number of diatomic materials. This paper reviews a number of previous results that elucidate the effects of atomic mass, recoil energy, displacement energy, capture energy and material stoichiometry on the numbers of displacements in a cascade. The displacement cascade reveals a complex structure that is dependent on the type of irradiation and the material properties. Conclusions related to damage analysis for fusion reactors are given.

Parkin, D.M.; Coulter, C.A.

1982-01-01

151

Crack-opening displacement transducer  

NASA Technical Reports Server (NTRS)

Crack-opening displacement transducer consists of 30 deg cone, coil spring, and linear-displacement transducer. Conical probe is used to measure crack opening. Cone is pressed firmly into crack by spring. As applied load causes crack to open up, cone is pushed further into it. Movement of cone, and thus crack growth, is monitored by linear-displacement transducer. Method gives more accurate measurement of crack-opening displacement of very narrow slots.

Simonds, R. A.

1980-01-01

152

[Transplantation in peripheral nerve injuries].  

PubMed

Autologous nerve grafting is the most commocommnlynly used operative technique in delayed primary, or secondary nerve repair after the peripheral nerve injuries. The aim of this procedure is to overcome nerve gaps that results from the injury itself, fibrous and elastic retraction forces, resection of the damaged parts of the nerve, position of the articulations and mobilisation of the nerve. In this study we analyse the results of operated patients with transections and lacerations of the peripheral nerves from 1979 to 2000 year. Gunshot injuries have not been analyzed in this study. The majority of the injuries were in the upper extremity (more than 87% of cases). Donor for nerve transplantation had usually been sural nerve, and only occasionally medial cutaneous nerve of the forearm was used. In about 93% of cases we used interfascicular nerve grafting, and cable nerve grafting was performed in the rest of them. Most of the grafts were 1 do 5 cm long (70% of cases). Functional recovery was achieved in more than 86% of cases, which is similar to the results of the other authors. Follow up period was minimum 2 years. We analyzed the influence of different factors on nerve recovery after the operation: patient's age, location and the extent (total or partial) of nerve injury, the length of the nerve graft, type of the nerve, timing of surgery, presence of multiple nerve injuries and associated osseal and soft tissue injuries of the upper and lower extremities. PMID:14619715

Grujici?, D; Samardzi?, M; Rasuli?, L; Savi?, D; Cvrkota, I; Simi?, V

2003-01-01

153

Synthesis of finite displacements and displacements in continental margins  

NASA Technical Reports Server (NTRS)

The scope of the project is the analysis of displacement-rate fields in the transitional regions between cratonal and oceanic lithospheres over Phanerozoic time (last 700 ma). Associated goals are an improved understanding of range of widths of major displacement zones; the partition of displacement gradients and rotations with position and depth in such zones; the temporal characteristics of such zones-the steadiness, episodicity, and duration of uniform versus nonunifrom fields; and the mechanisms and controls of the establishment and kinematics of displacement zones. The objective is to provide a context of time-averaged kinematics of displacement zones. The initial phase is divided topically among the methodology of measurement and reduction of displacements in the lithosphere and the preliminary analysis from geologic and other data of actual displacement histories from the Cordillera, Appalachians, and southern North America.

Speed, R. C.; Elison, M. W.; Heck, F. R.; Russo, R. M.

1988-01-01

154

Anatomy and function of sensory hepatic nerves.  

PubMed

Vagal and spinal afferent innervation of the portal hepatic area has not been studied as thoroughly as the innervation of other important organs. It is generally agreed that unlike noradrenergic sympathetic efferent nerve fibers, sensory nerve fibers of either vagal or dorsal root/spinal origin do not directly innervate hepatocytes, but are restricted to the stroma surrounding triades of hepatic vasculature and bile ducts, and to extrahepatic portions of the portal vein and bile ducts. For vagal afferent innervation, retrograde and anterograde tracing studies in the rat have clearly shown that only a minor portion of the common hepatic branch innervates the liver area, while the major portion descends in the gastroduodenal branch toward duodenum, pancreas, and pylorus. Hepatic paraganglia, bile ducts, and portal vein receive the densest vagal afferent innervation. Calretinin may be a relatively specific marker for vagal afferent innervation of the portal-hepatic space. Calcitonin gene-related peptide (CGRP) is a specific marker for dorsal root afferents, and CGRP-immunoreactive fibers are mainly present near the intrahepatic vascular bundles and bile ducts, and in the same extrahepatic compartments that contain vagal afferents. Because of the specific anatomical organization of hepatic nerves, selective hepatic denervation, whether selective for the vagal or sympathetic division, or for efferents and afferents, is nearly impossible. Great caution is therefore necessary when interpreting functional outcomes of so-called specific hepatic denervation studies. PMID:15382018

Berthoud, Hans-Rudolf

2004-09-01

155

Upper Limb Neurodynamic Test 2Median Nerve Bias: An Investigation of Examiner Reliability, End-Range Shoulder Abduction, and Symptom Response in Asymptomatic Subjects  

Microsoft Academic Search

Background and purpose: The Upper Limb Tension Test (ULTT) has been established as a physical therapy examination tool to assist in assessment of the cervical nerve roots and peripheral nerves as possible components contributing to upper limb symptoms in patients. Research has focused on the use of the ULTT in assessment of asymptomatic individuals, and on the ULTT2-Radial Nerve Bias,

Rebecca Reisch; Kimberly Williams

2001-01-01

156

Advances in nerve repair.  

PubMed

Patients with peripheral nerve injuries face unpredictable and often suboptimal functional outcome, even following standard microsurgical nerve repair. The challenge of improving such outcomes following nerve surgical procedures has interested many research teams, in both clinical and fundamental fields. Some innovative treatments are presently being applied to a widening range of patients, whereas others will require further development before translation to human subjects. This article presents several recent advances in emerging therapies at various stages of clinical application. Nerve transfers have been successfully used in clinical settings, but new indications are being described, enlarging the range of patients who might benefit from them. Brief direct nerve electrical stimulation has been shown to improve nerve regeneration and outcome in animal models and in a small cohort of patients. Further clinical trials are warranted to prove the efficacy of this exciting and easily applicable approach. Animal studies also suggest a tremendous potential for stem and precursor cell therapy. Further studies will lead to a better understanding of their mechanisms of action in nerve repair and potential applications for human patients. PMID:23250767

Khuong, Helene T; Midha, Rajiv

2013-01-01

157

Anterior interosseous nerve syndrome  

PubMed Central

Objective: We sought to determine lesion sites and spatial lesion patterns in spontaneous anterior interosseous nerve syndrome (AINS) with high-resolution magnetic resonance neurography (MRN). Methods: In 20 patients with AINS and 20 age- and sex-matched controls, MRN of median nerve fascicles was performed at 3T with large longitudinal anatomical coverage (upper arm/elbow/forearm): 135 contiguous axial slices (T2-weighted: echo time/repetition time 52/7,020 ms, time of acquisition: 15 minutes 48 seconds, in-plane resolution: 0.25 × 0.25 mm). Lesion classification was performed by visual inspection and by quantitative analysis of normalized T2 signal after segmentation of median nerve voxels. Results: In all patients and no controls, T2 lesions of individual fascicles were observed within upper arm median nerve trunk and strictly followed a somatotopic/internal topography: affected were those motor fascicles that will form the anterior interosseous nerve further distally while other fascicles were spared. Predominant lesion focus was at a mean distance of 14.6 ± 5.4 cm proximal to the humeroradial joint. Discriminative power of quantitative T2 signal analysis and of qualitative lesion rating was high, with 100% sensitivity and 100% specificity (p < 0.0001). Fascicular T2 lesion patterns were rated as multifocal (n = 17), monofocal (n = 2), or indeterminate (n = 1) by 2 independent observers with strong agreement (kappa = 0.83). Conclusion: It has been difficult to prove the existence of fascicular/partial nerve lesions in spontaneous neuropathies using clinical and electrophysiologic findings. With MRN, fascicular lesions with strict somatotopic organization were observed in upper arm median nerve trunks of patients with AINS. Our data strongly support that AINS in the majority of cases is not a surgically treatable entrapment neuropathy but a multifocal mononeuropathy selectively involving, within the main trunk of the median nerve, the motor fascicles that continue distally to form the anterior interosseous nerve. PMID:24415574

Baumer, Philipp; Meinck, Hans-Michael; Schiefer, Johannes; Weiler, Markus; Bendszus, Martin; Kele, Henrich

2014-01-01

158

The nerve injury and the dying neurons: diagnosis and prevention  

Microsoft Academic Search

Following distal nerve injury significant sensory neuronal cell death occurs in the dorsal root ganglia, while after a more proximal injury, such as brachial plexus injury, a sizeable proportion of spinal motoneurons also undergo cell death. This phenomenon has been undervalued for a long time, but it has a significant role in the lack of functional recuperation, as neuronal cells

G. Terenghi; A. Hart; M. Wiberg

2011-01-01

159

Glossopharyngeal Nerve Schwannoma  

PubMed Central

Complete resection with conservation of cranial nerves is the primary goal of contemporary surgery for lower cranial nerve tumors. We describe the case of a patient with a schwannoma of the left glossopharyngeal nerve, operated on in our Neurosurgical Unit. The far lateral approach combined with laminectomy of the posterior arch of C1 was done in two steps. The procedure allowed total tumor resection and was found to be better than classic unilateral suboccipital or combined supra- and infratentorial approaches. The advantages and disadvantages of the far lateral transcondylar approach, compared to the other more common approaches, are discussed. ImagesFigure 1Figure 2 PMID:17171083

Puzzilli, F.; Mastronardi, L.; Agrillo, U.; Nardi, P.

1999-01-01

160

Angular displacement measuring device  

NASA Technical Reports Server (NTRS)

A system for measuring the angular displacement of a point of interest on a structure, such as aircraft model within a wind tunnel, includes a source of polarized light located at the point of interest. A remote detector arrangement detects the orientation of the plane of the polarized light received from the source and compares this orientation with the initial orientation to determine the amount or rate of angular displacement of the point of interest. The detector arrangement comprises a rotating polarizing filter and a dual filter and light detector unit. The latter unit comprises an inner aligned filter and photodetector assembly which is disposed relative to the periphery of the polarizer so as to receive polarized light passing the polarizing filter and an outer aligned filter and photodetector assembly which receives the polarized light directly, i.e., without passing through the polarizing filter. The purpose of the unit is to compensate for the effects of dust, fog and the like. A polarization preserving optical fiber conducts polarized light from a remote laser source to the point of interest.

Seegmiller, H. Lee B. (inventor)

1992-01-01

161

A novel chondroitin sulfate hydrogel for nerve repair  

NASA Astrophysics Data System (ADS)

Brachial plexus injuries affect numerous patients every year, with very debilitating results. The majority of these cases are very severe, and involve damage to the nerve roots. To date, repair strategies for these injuries address only gross tissue damage, but do not supply cells with adequate regeneration signals. As a result, functional recovery is often severely lacking. Therefore, a chondroitin sulfate hydrogel that delivers neurotrophic signals to damaged neurons is proposed as a scaffold to support nerve root regeneration. Capillary electrophoresis studies revealed that chondroitin sulfate can physically bind with a variety of neurotrophic factors, and cultures of chick dorsal root ganglia demonstrated robust neurite outgrowth in chondroitin sulfate hydrogels. Outgrowth in chondroitin sulfate gels was greater than that observed in control gels of hyaluronic acid. Furthermore, the chondroitin sulfate hydrogel's binding activity with nerve growth factor could be enhanced by incorporation of a synthetic bioactive peptide, as revealed by fluorescence recovery after photobleaching. This enhanced binding was observed only in chondroitin sulfate gels, and not in hyaluronic acid control gels. This enhanced binding activity resulted in enhanced dorsal root ganglion neurite outgrowth in chondroitin sulfate gels. Finally, the growth of regenerating dorsal root ganglia in these gels was imaged using label-free coherent anti-Stokes scattering microscopy. This technique generated detailed, high-quality images of live dorsal root ganglion neurites, which were comparable to fixed, F-actin-stained samples. Taken together, these results demonstrate the viability of this chondroitin sulfate hydrogel to serve as an effective implantable scaffold to aid in nerve root regeneration.

Conovaloff, Aaron William

162

Adapting to variable prismatic displacement  

NASA Technical Reports Server (NTRS)

In each of two studies, subjects were exposed to a continuously changing prismatic displacement with a mean value of 19 prism diopters (variable displacement) and to a fixed 19-diopter displacement (fixed displacement). In Experiment 1, significant adaptation (post-pre shifts in hand-eye coordination) was found for fixed, but not for variable, displacement. Experiment 2 demonstrated that adaptation was obtained for variable displacement, but it was very fragile and is lost if the measures of adaptation are preceded by even a very brief exposure of the hand to normal or near-normal vision. Contrary to the results of some previous studies, an increase in within-S dispersion was not found of target pointing responses as a result of exposure to variable displacement.

Welch, Robert B.; Cohen, Malcolm M.

1989-01-01

163

Perineural tumor spread - Interconnection between spinal and cranial nerves.  

PubMed

The secondary neoplastic involvement of the cervical plexus in patients with head and neck malignancies is extremely rare. MR examination of the neck revealed the diffuse neoplastic infiltration of the right C2 root, in a 57-year-old patient with several months long pain in the right ear region and a history of the tongue squamous cell carcinoma. Associated perineural tumor spread and consequent distal involvement of great auricular nerve and vagus nerve were evident. Best of our knowledge, this is the first reported involvement of the cervical plexus in patients with head and neck cancers, associated with the clearly documented interconnection between the cervical plexus and cranial nerves via great auricular nerve. PMID:23010545

Kozi?, Duško; Njagulj, Vesna; Ga?eša, Jelena Popadi?; Semnic, Robert; Prvulovi?, Nataša

2012-12-15

164

Diabetic Nerve Problems  

MedlinePLUS

... at the wrong times. This damage is called diabetic neuropathy. Over half of people with diabetes get it. ... you change positions quickly Your doctor will diagnose diabetic neuropathy with a physical exam and nerve tests. Controlling ...

165

Lower cranial nerves.  

PubMed

Imaging evaluation of cranial neuropathies requires thorough knowledge of the anatomic, physiologic, and pathologic features of the cranial nerves, as well as detailed clinical information, which is necessary for tailoring the examinations, locating the abnormalities, and interpreting the imaging findings. This article provides clinical, anatomic, and radiological information on lower (7th to 12th) cranial nerves, along with high-resolution magnetic resonance images as a guide for optimal imaging technique, so as to improve the diagnosis of cranial neuropathy. PMID:24210311

Soldatos, Theodoros; Batra, Kiran; Blitz, Ari M; Chhabra, Avneesh

2014-02-01

166

Variable displacement blower  

DOEpatents

A blower having a stationary casing for rotatably supporting a rotor assembly having a series of open ended chambers arranged to close against the surrounding walls of the casing. Pistons are slidably mounted within each chamber with the center of rotation of the pistons being offset in regard to the center of rotation of the rotor assembly whereby the pistons reciprocate in the chambers as the rotor assembly turns. As inlet port communicates with the rotor assembly to deliver a working substance into the chamber as the pistons approach a top dead center position in the chamber while an outlet port also communicates with the rotor to exhaust the working substance as the pistons approach a bottom dead center position. The displacement of the blower is varied by adjusting the amount of eccentricity between the center of rotation of the pistons and the center of rotation of the rotor assembly.

Bookout, Charles C. (Niskayuna, NY); Stotts, Robert E. (Clifton Park, NY); Waring, Douglass R. (Ballston Spa, NY); Folsom, Lawrence R. (Ohain, BE)

1986-01-01

167

Bladder emptying by intermittent electrical stimulation of the pudendal nerve  

NASA Astrophysics Data System (ADS)

Persons with a suprasacral spinal cord injury cannot empty their bladder voluntarily. Bladder emptying can be restored by intermittent electrical stimulation of the sacral nerve roots (SR) to cause bladder contraction. However, this therapy requires sensory nerve transection to prevent dyssynergic contraction of the external urethral sphincter (EUS). Stimulation of the compound pudendal nerve trunk (PN) activates spinal micturition circuitry, leading to a reflex bladder contraction without a reflex EUS contraction. The present study determined if PN stimulation could produce bladder emptying without nerve transection in cats anesthetized with ?-chloralose. With all nerves intact, intermittent PN stimulation emptied the bladder (64 ± 14% of initial volume, n = 37 across six cats) more effectively than either distention-evoked micturition (40 ± 19%, p < 0.001, n = 27 across six cats) or bilateral intermittent SR stimulation (25 ± 23%, p < 0.005, n = 4 across two cats). After bilateral transection of the nerves innervating the urethral sphincter, intermittent SR stimulation voided 79 ± 17% (n = 12 across three cats), comparable to clinical results obtained with SR stimulation. Voiding via intermittent PN stimulation did not increase after neurotomy (p > 0.10), indicating that PN stimulation was not limited by bladder-sphincter dyssynergia. Intermittent PN stimulation holds promise for restoring bladder emptying following spinal injury without requiring nerve transection.

Boggs, Joseph W.; Wenzel, Brian J.; Gustafson, Kenneth J.; Grill, Warren M.

2006-03-01

168

Histopathological effects of radiosurgery on a human trigeminal nerve  

PubMed Central

Background: Radiosurgery is a well-established treatment modality for medically refractory trigeminal neuralgia. The exact mechanism of pain relief after radiosurgery is not clearly understood. Histopathology examination of the trigeminal nerve in humans after radiosurgery is rarely performed and has produced controversial results. Case Description: We report on a 45-year-old female who received radiosurgery treatment for trigeminal neuralgia by Cyberknife. A 6-mm portion of the cisternal segment of trigeminal nerve received a dose of 60 Gy. The clinical benefit started 10 days after therapy and continued for 8 months prior to a recurrence of her previous symptoms associated with mild background pain. She underwent microvascular decompression and partial sensory root sectioning. Atrophied trigeminal nerve rootlets were grossly noted intraoperatively under surgical microscope associated with changes in trigeminal nerve color to gray. A biopsy from the inferolateral surface of the nerve proximal to the midcisternal segment showed histological changes in the form of fibrosis and axonal degeneration. Conclusion: This case study supports the evidence of histological damage of the trigeminal nerve fibers after radiosurgery therapy. Whether or not the presence and degree of nerve damage correlate with the degree of clinical benefit and side effects are not revealed by this study and need to be explored in future studies. PMID:24605252

Al-Otaibi, Faisal; Alhindi, Hindi; Alhebshi, Adnan; Albloushi, Monirah; Baeesa, Saleh; Hodaie, Mojgan

2013-01-01

169

Role of the hypoglossal nerve in equine nasopharyngeal stability.  

PubMed

The equine upper airway is highly adapted to provide the extremely high oxygen demand associated with strenuous aerobic exercise in this species. The tongue musculature, innervated by the hypoglossal nerve, plays an important role in airway stability in humans who also have a highly adapted upper airway to allow speech. The role of the hypoglossal nerve in stabilizing the equine upper airway has not been established. Isolated tongues from eight mature horses were dissected to determine the distal anatomy and branching of the equine hypoglossal nerve. Using this information, a peripheral nerve location technique was used to perform bilateral block of the common trunk of the hypoglossal nerve in 10 horses. Each horse was subjected to two trials with bilateral hypoglossal nerve block and two control trials (unblocked). Upper airway stability at exercise was determined using videoendoscopy and measurement of tracheal and pharyngeal pressure. Three main nerve branches were identified, medial and lateral branches and a discrete branch that innervated the geniohyoid muscle alone. Bilateral hypoglossal block induced nasopharyngeal instability in 10/19 trials, and none of the control trials (0/18) resulted in instability (P<0.001). Mean treadmill speed (+/-SD) at the onset of instability was 10.8+/-2.5 m/s. Following its onset, nasopharyngeal instability persisted until the end of the treadmill test. This instability, induced by hypoglossal nerve block, produced an expiratory obstruction similar to that seen in a naturally occurring equine disease (dorsal displacement of the soft palate, DDSP) with reduced inspiratory and expiratory pharyngeal pressure and increased expiratory tracheal pressure. These data suggest that stability of the equine upper airway at exercise may be mediated through the hypoglossal nerve. Naturally occurring DDSP in the horse shares a number of anatomic similarities with obstructive sleep apnea. Study of species with extreme respiratory adaptation, such as the horse, may provide insight into respiratory functioning in humans. PMID:19498094

Cheetham, Jonathan; Pigott, John H; Hermanson, John W; Campoy, Luis; Soderholm, Leo V; Thorson, Lisa M; Ducharme, Norm G

2009-08-01

170

Microsurgical repair of nerve lesions with nerve grafts: the effect of nerve growth factor 7S  

Microsoft Academic Search

This study investigated the effect of local administration of nerve growth factor 7S (NGF-7S) on the axonal regrowth of mixed peripheral nerves through nerve grafts. Sixty male Wistar rats were randomized into two groups (n=30). A defect 12 mm long in the right sciatic nerve was created and repaired with a nerve autograft. NGF-7S (group A) or normal saline (group

Andreas I. Gravvanis; Efstathios G. Lykoudis; George A. Tagaris; Charalampos G. Patralexis; Apostolos E. Papalois; Petros N. Panayotou; Constantinos N. Stamatopoulos; John D. Ioannovich

2002-01-01

171

Peripheral Nerve Repair in Rats Using Composite Hydrogel-Filled Aligned Nanofiber Conduits with Incorporated Nerve Growth Factor  

PubMed Central

Repair of peripheral nerve defects with current synthetic, tubular nerve conduits generally shows inferior recovery when compared with using nerve autografts, the current gold standard. We tested the ability of composite collagen and hyaluronan hydrogels, with and without the nerve growth factor (NGF), to stimulate neurite extension on a promising aligned, nanofiber poly-L-lactide-co-caprolactone (PLCL) scaffold. In vitro, the hydrogels significantly increased neurite extension from dorsal root ganglia explants. Consistent with these results, the addition of hydrogels as luminal fillers within aligned, nanofiber tubular PLCL conduits led to improved sensory function compared to autograft repair in a critical-size defect in the sciatic nerve in a rat model. Sensory recovery was assessed 3 and 12 weeks after repair using a withdrawal assay from thermal stimulation. The addition of hydrogel did not enhance recovery of motor function in the rat model. The NGF led to dose-dependent improvements in neurite out-growth in vitro, but did not have a significant effect in vivo. In summary, composite collagen/hyaluronan hydrogels enhanced sensory neurite outgrowth in vitro and sensory recovery in vivo. The use of such hydrogels as luminal fillers for tubular nerve conduits may therefore be useful in assisting restoration of protective sensation following peripheral nerve injury. PMID:23659607

Jin, Jenny; Limburg, Sonja; Joshi, Sunil K.; Landman, Rebeccah; Park, Michelle; Zhang, Qia; Kim, Hubert T.

2013-01-01

172

[Gross and light microscopic observations of the pudendal nerve of the guinea pig (author's transl)].  

PubMed

Using thirty six adult guinea pigs, the course and distribution of the pudendal nerve was observed macroscopically and then the constitution of the myelinated nerve fibers in these branches was studied with the fan-wise split preparation method (Fukuyama) and the cross sections embeded in paraffin wax. The main findings are summarized as follows: 1) The pudendal plexus in the guinea pig is formed most frequently by a bigeminal nerve which arises from the ventral ramus of the second sacral nerve at an average rate of 55.0% and the pudendal nerve is so independent from the sciatic nerve that the most part of the bigeminal nerve runs into the pudendal nerve. 2) The perineal nerve of the guinea pig arises most frequently with four roots (43.3%). The myelinated fiber constitution of this nerve is as follows: The small-sized fibers occupy 49.8%, the medium--sized 21.9%, the large--sized 15.1%, the maximum--sized 13.1% on an average, and the nerve fiber diameters observed in the cross section shows a bimodality in their distribution, of which the fibers in the higher peak are 1 mu to 2 mu and in the lower peak 5 mu to 8 mu. 3) The dorsal nerve of the penis or clitoris of the guinea pig arises most frequently with one root from the originating roots of the perineal nerve. The relationship between the sciatic and dorsal nerve appears to be scanty. The myelinated fibers of this nerve comprise 50.8% of small--sized, 28.4% of medium--sized, 14.7% of large--sized and 6.2% of maximum--sized fibers on an average. The fiber sized histograms constructed in the cross section shows a unimodality laying at 1 mu to 3 mu and the dorsal nerve of the clitoris contains more medium fibers 3 mu to 6 mu than the perineal nerve. From these results, it seems clear that the genital corpuscles are supplied by these medium fibers. 4) The inferior rectal nerve of the guinea pig arises from the perineal nerve in all cases, however, it is very slender. 5) The branch to the Obturator internus arises from the originating root or main trunck of the perineal nerve (51.7%). The myelinated fiber constitution of this branch is as follows: The maximum--sized fibers occupy 67.6%, the large--sized 16.2%, the small--sized 9.5% and the medium sized 6.8%. On the other hand, the fiber diameters observed in the transverse section are distributed around three peaks lying at 1 mu, 8 mu to 9 mu and 12 mu to 13 mu. 6) The branch to the accessory head of the Semitendinosus arises from the pudendal nerve at an average rate of 91.7%, of which this branch arises most frequently with one root from the originating root of the perineal nerve. The myelinated fiber constitution is as follows: The maximum--sized fibers 50.0%, the large--sized 23.9%, the small--sized 15.9% and the medium--sized 10.2% on an average. The histogram shows that myelinated fibers in this muscular branch consist of two groups of 1 mu to 2 mu and 12 mu to 14 mu... PMID:1034612

Kanno, Y

1976-09-01

173

[Nerve transfer in brachial plexus injuries--comparative analysis of surgical procedures].  

PubMed

Nerve transfer is the only possibility for nerve repair in cases of the brachial plexus traction injuries with spinal roots avulsion. From 1980. until 2000. in Institute of Neurosurgery, Clinical Center of Serbia, nerve transfer has been performed in 127(79%) of 159 patients with traction injuries of brachial plexus, i.e., 204 reinnervation procedures has been performed using different donor nerves. We achieved good or satisfactory arm abduction and full range or satisfactory elbow flexion through reinnervation of the axillary and musculocutaneous nerve using different donor nerves in 143 of 204 reinnervations, which presents general rate of useful functional recovery in 70.1% of cases. Mean values of the rate of useful functional recovery in individual modalities of nerve transfer in our series are 50.1% for intercostal and/or spinal accessory nerve transfer, 64.5% for plexo-plexal nerve transfer, 81.7% for regional nerve transfer, and 87.1% for combine nerve transfer. PMID:14619714

Rasuli?, L; Samardzi?, M; Grujici?, D; Bascarevi?, V

2003-01-01

174

The measurement of gas spaces in the roots of aquatic plants — Archimedes revisited  

Microsoft Academic Search

The volume of gas space within the root systems of pot-grown mangrove plants was determined by three methods based on Archimedes' principle: pycnometry, measurement of the upthrust on the root system when immersed in water, and measurement of the volume of water displaced. The results obtained using the upthrust and displacement methods were highly consistent. Although individual estimates obtained by

Mark Curran; Peter James; William G. Allaway

1996-01-01

175

Repair of sciatic nerve defects using tissue engineered nerves.  

PubMed

In this study, we constructed tissue-engineered nerves with acellular nerve allografts in Sprague-Dawley rats, which were prepared using chemical detergents-enzymatic digestion and mechanical methods, in combination with bone marrow mesenchymal stem cells of Wistar rats cultured in vitro, to repair 15 mm sciatic bone defects in Wistar rats. At postoperative 12 weeks, electrophysiological detection results showed that the conduction velocity of regenerated nerve after repair with tissue-engineered nerves was similar to that after autologous nerve grafting, and was higher than that after repair with acellular nerve allografts. Immunohistochemical staining revealed that motor endplates with acetylcholinesterase-positive nerve fibers were orderly arranged in the middle and superior parts of the gastrocnemius muscle; regenerated nerve tracts and sprouted branches were connected with motor endplates, as shown by acetylcholinesterase histochemistry combined with silver staining. The wet weight ratio of the tibialis anterior muscle at the affected contralateral hind limb was similar to the sciatic nerve after repair with autologous nerve grafts, and higher than that after repair with acellular nerve allografts. The hind limb motor function at the affected side was significantly improved, indicating that acellular nerve allografts combined with bone marrow mesenchymal stem cell bridging could promote functional recovery of rats with sciatic nerve defects. PMID:25206507

Zhang, Caishun; Lv, Gang

2013-07-25

176

Root gravitropism  

NASA Technical Reports Server (NTRS)

When a plant root is reoriented within the gravity field, it responds by initiating a curvature which eventually results in vertical growth. Gravity sensing occurs primarily in the root tip. It may involve amyloplast sedimentation in the columella cells of the root cap, or the detection of forces exerted by the mass of the protoplast on opposite sides of its cell wall. Gravisensing activates a signal transduction cascade which results in the asymmetric redistribution of auxin and apoplastic Ca2+ across the root tip, with accumulation at the bottom side. The resulting lateral asymmetry in Ca2+ and auxin concentration is probably transmitted to the elongation zone where differential cellular elongation occurs until the tip resumes vertical growth. The Cholodny-Went theory proposes that gravity-induced auxin redistribution across a gravistimulated plant organ is responsible for the gravitropic response. However, recent data indicate that the gravity-induced reorientation is more complex, involving both auxin gradient-dependent and auxin gradient-independent events.

Masson, P. H.

1995-01-01

177

Inflammatory pseudotumor of nerve.  

PubMed

Two cases of inflammatory pseudotumor are described. The first patient, a 35-year-old white man, developed a progressive sensorimotor deficit in the right leg associated with a fusiform sciatic nerve mass in the posterior thigh. The lesion, compressive in nature and situated entirely within the epineurium, was totally resected. Histology revealed lymphocytic and plasmacellular inflammation as well as extensive fibrosis and collagen deposition. The patchy infiltrate consisted equally of CD2, CD3, CD5, and CD7 positive T-lymphocytes as well as CD20-and CD22-positive B-lymphocytes expressing both kappa and lambda immunoglobulin light chains. A selective biopsy of the encompassed and compressed nerve fascicles demonstrated both myelin loss and axonal injury. The second case was that of an 18-year-old woman with focal enlargement of a radial nerve by an epineurial infiltrate of multinucleate histiocytes and T as well as occasional B lymphocytes. No etiology was apparent in either case. The differential diagnosis includes non-neoplastic processes (amyloidoma and tuberculoid leprosy) as well as tumors (benign and malignant peripheral nerve sheath tumors, lymphoma). Although rare, inflammatory pseudotumors must be included in the differential diagnosis of tumor-like lesions of peripheral nerve. PMID:8827027

Weiland, T L; Scheithauer, B W; Rock, M G; Sargent, J M

1996-10-01

178

Displacement, Substitution, Sublimation: A Bibliography.  

ERIC Educational Resources Information Center

Sigmund Freund worked with the mechanisms of displacement, substitution, and sublimation. These mechanisms have many similarities and have been studied diagnostically and therapeutically. Displacement and substitution seem to fit in well with phobias, hysterias, somatiyations, prejudices, and scapegoating. Phobias, prejudices, and scapegoating…

Pedrini, D. T.; Pedrini, Bonnie C.

179

CHARACTER DISPLACEMENT IN POLYPHENIC TADPOLES  

Microsoft Academic Search

Biologists have long known that closely related species are often phenotypically different where they occur together, but are indistinguishable where they occur alone. The causes of such character displacement are controversial, however. We used polyphenic spadefoot toad tadpoles (Spea bombifrons and S. multiplicata) to test the hypothesis that character displacement evolves to minimize competition for food. We also sought to

David W. Pfennig; Peter J. Murphy

2000-01-01

180

Coding of position by simultaneously recorded sensory neurones in the cat dorsal root ganglion  

PubMed Central

Muscle, cutaneous and joint afferents continuously signal information about the position and movement of individual joints. How does the nervous system extract more global information, for example about the position of the foot in space? To study this question we used microelectrode arrays to record impulses simultaneously from up to 100 discriminable nerve cells in the L6 and L7 dorsal root ganglia (DRG) of the anaesthetized cat. When the hindlimb was displaced passively with a random trajectory, the firing rate of the neurones could be predicted from a linear sum of positions and velocities in Cartesian (x, y), polar or joint angular coordinates. The process could also be reversed to predict the kinematics of the limb from the firing rates of the neurones with an accuracy of 1–2 cm. Predictions of position and velocity could be combined to give an improved fit to limb position. Decoders trained using random movements successfully predicted cyclic movements and movements in which the limb was displaced from a central point to various positions in the periphery. A small number of highly informative neurones (6–8) could account for over 80% of the variance in position and a similar result was obtained in a realistic limb model. In conclusion, this work illustrates how populations of sensory receptors may encode a sense of limb position and how the firing of even a small number of neurones can be used to decode the position of the limb in space. PMID:15331686

Stein, R B; Weber, D J; Aoyagi, Y; Prochazka, A; Wagenaar, J B M; Shoham, S; Normann, R A

2004-01-01

181

Displacement cascades in diatomic materials  

SciTech Connect

A new function, the specified-projectile displacement function p/sub ijk/ (E), is introduced to describe displacement cascades in polyatomic materials. This function describes the specific collision events that produce displacements and hence adds new information not previously available. Calculations of p/sub ijk/ (E) for MgO, Al/sub 2/O/sub 3/ and TaO are presented and discussed. Results show that the parameters that have the largest effect on displacement collision events are the PKA energy and the mass ratio of the atom types in the material. It is further shown that the microscopic nature of the displacement events changes over the entire recoil energy range relevant to fusion neutron spectra and that these changes are different in materials whose mass ratio is near one than in those where it is far from one.

Parkin, D.M.; Coulter, C.A.

1981-01-01

182

Laryngeal nerve monitoring.  

PubMed

Intraoperative neurophysiological monitoring of the vagus and recurrent laryngeal nerves is increasingly used during thyroidectomy, parathyroidectomy, skull base surgery, and cervical discectomy with fusion. Monitoring can assist in nerve localization and in reducing the incidence of neural trauma. To be effective, however, monitoring must be correctly implemented and the results interpreted based on an in-depth understanding of technique and the surgical structures at risk. Because "poor monitoring is worse than no monitoring" all members of the surgical monitoring team must have training specific to laryngeal recording to maximize its benefit and minimize pitfalls. This publication will review pertinent anatomy and neurophysiology as well as technical and interpretative factors. PMID:25351033

Kartush, Jack M; Naumann, Ilka

2014-09-01

183

Damage-Induced Neuronal Endopeptidase (DINE\\/ECEL) Expression Is Regulated by Leukemia Inhibitory Factor and Deprivation of Nerve Growth Factor in Rat Sensory Ganglia after Nerve Injury  

Microsoft Academic Search

Damage-induced neuronal endopeptidase (DINE) is a novel metallopeptidase and is expressed in response to various neu- ronal injuries. The expression regulation of DINE mRNA in the dorsal root ganglia (DRGs) after sciatic nerve injury is examined. A substantial increase of DINE mRNA expression was observed in relatively small-sized DRG neurons after nerve injury. The expression was observed in isolectin B4-negative

Ryuichi Kato; Sumiko Kiryu-Seo; Hiroshi Kiyama

2002-01-01

184

Functional electrical stimulation of the left recurrent laryngeal nerve using a vagus nerve stimulator in a normal horse.  

PubMed

The aim of this study was to assess the feasibility of implanting an existing vagus nerve stimulating (VNS) electrode around the recurrent laryngeal nerve. The stimulus response characteristics required to achieve abduction of the ipsilateral arytenoid by the VNS electrode in the normal horse could then be determined. The electrode was wound around the left recurrent laryngeal nerve at the cervical level and connected to a pulse generator. Stimulus response characteristics were obtained by measuring stimulated arytenoid displacement endoscopically in the standing, non-sedated horse. A full and sustained abduction of the arytenoid was obtained with a stimulation frequency of 25 Hz and intensity of 1 mA with a pulse width of 250 ?s. PMID:20724182

Vanschandevijl, Katleen; Nollet, Heidi; Vonck, Kristl; Raedt, Rorecht; Boon, Paul; Roost, DirkVan; Martens, Ann; Deprez, Piet

2011-09-01

185

Airway nerves: in vivo electrophysiology  

Microsoft Academic Search

Information about the activity of airway sensory afferent nerves in vivo can be obtained electrophysiologically by extracellular recording of action potentials. Apart from data capture, the basic techniques used for recording sensory nerve activity have not advanced greatly in 50 years. However, clearly they continue to contribute vastly to our understanding of the role of these nerves in the control

John J Adcock

2002-01-01

186

Fibrolipoma of the median nerve  

Microsoft Academic Search

Neural fibrolipoma or fibrolipomatous hamartoma is an uncommon benign tumor that usually arises in the median nerve. Fibrofatty tissue proliferates around the nerve and infiltrates the epineurium and perineurium. We report a case of fibrolipomatous hamartoma of the left median nerve in an 18-year-old woman. Our objective was to describe the pathognomonic magnetic resonance imaging features, whose presence obviates the

Kais Nouira; Hend Belhiba; Sofiène Baccar; Anissa Miaaoui; Monia Ben Messaoud; Imène Turki; Ilhem Cheour; Emna Menif

2007-01-01

187

Regenerative rotary displacer Stirling engine  

SciTech Connect

A few rotary displacer Stirling engines in which the displacer has one gas pocket space at one side and rotates in a main enclosed cylinder, which is heated from one side and cooled from opposite side without any regenerator, have been studied for some time by the authors. The authors tried to improve this engine by equipping it with a regenerator, because without a regenerator, pressure oscillation and efficiency are too small. Here, several types of regenerative rotary displacer piston Stirling engines are proposed. One is the contra-rotating tandem two disc type displacer engine using axial heat conduction through side walls or by heat pipes and another is a single disc type with circulating fluid regenerator or heat pipes. Stirling engines of this new rotary displacer type are thought to attain high speed. Here, experimental results of the original rotary displacer Stirling engine without a regenerator, and one contra-rotating tandem displacer engine with side wall regenerator by axial heat conduction are reported accompanied with a discussion of the results.

Isshiki, Naotsugu; Watanabe, Hiroichi [Nihon Univ. Tokyo (Japan); Raggi, L. [Waseda Univ., Tokyo (Japan); Isshiki, Seita; Hirata, Koichi

1996-12-31

188

Ischemic Nerve Block.  

ERIC Educational Resources Information Center

This experiment investigated the capability for movement and muscle spindle function at successive stages during the development of ischemic nerve block (INB) by pressure cuff. Two male subjects were observed under six randomly ordered conditions. The duration of index finger oscillation to exhaustion, paced at 1.2Hz., was observed on separate…

Williams, Ian D.

189

Iatrogenic nerve injuries  

PubMed Central

Thirty-one examples of iatrogenic peripheral nerve injuries have been collected from a review of the case records of one neurological referral centre over a 7-year period. The clinical details are described to call attention to the special care needed with the management of patients subjected to certain invasive procedures. PMID:7100035

Winer, J. B.; Harrison, M. J. G.

1982-01-01

190

Segmental thoracic lipomatosis of nerve with nerve territory overgrowth.  

PubMed

Lipomatosis of nerve (LN), or fibrolipomatous hamartoma, is a rare condition of fibrofatty enlargement of the peripheral nerves. It is associated with bony and soft tissue overgrowth in approximately one-third to two-thirds of cases. It most commonly affects the median nerve at the carpal tunnel or digital nerves in the hands and feet. The authors describe a patient with previously diagnosed hemihypertrophy of the trunk who had a history of large thoracic lipomas resected during infancy, a thoracic hump due to adipose proliferation within the thoracic paraspinal musculature, and scoliotic deformity. She had fatty infiltration in the thoracic spinal nerves on MRI, identical to findings pathognomonic of LN at better-known sites. Enlargement of the transverse processes at those levels and thickened ribs were also found. This case appears to be directly analogous to other instances of LN with overgrowth, except that this case involved axial nerves rather than the typical appendicular nerves. PMID:24506247

Mahan, Mark A; Amrami, Kimberly K; Howe, B Matthew; Spinner, Robert J

2014-05-01

191

Borehole optical lateral displacement sensor  

DOEpatents

There is provided by this invention an optical displacement sensor that utilizes a reflective target connected to a surface to be monitored to reflect light from a light source such that the reflected light is received by a photoelectric transducer. The electric signal from the photoelectric transducer is then imputed into electronic circuitry to generate an electronic image of the target. The target`s image is monitored to determine the quantity and direction of any lateral displacement in the target`s image which represents lateral displacement in the surface being monitored. 4 figs.

Lewis, R.E.

1998-10-20

192

Variable spatial magnetic field influences peripheral nerves regeneration in rats.  

PubMed

Generator of spatial magnetic field is one of most recent achievements among the magnetostimulators. This apparatus allows to obtain the rotating magnetic field. This new method may be more effective than other widely used techniques of magnetostimulation and magnetotherapy. We investigated the influence of alternating, spatial magnetic field on the regeneration of the crushed rat sciatic nerves. Functional and morphological evaluations were used. After crush injury of the right sciatic nerve, Wistar C rats (n?=?80) were randomly divided into four groups (control and three experimental). The experimental groups (A, B, C) were exposed (20?min/day, 5?d/week, 4 weeks) to alternating spatial magnetic field of three different intensities. Sciatic Functional Index (SFI) and tensometric assessments were performed every week after nerve crush. Forty-eight hours before the sacrificing of animals, DiI (1,1'-di-octadecyl-3,3,3',3'-tetramethyloindocarbocyanine perchlorate) was applied 5?mm distally to the crush site. Collected nerves and dorsal root ganglia (DRG) were subjected to histological and immunohistochemical staining. The survival rate of DRG neurons was estimated. Regrowth and myelination of the nerves was examined. The results of SFI and tensometric assessment showed improvement in all experimental groups as compared to control, with best outcome observed in group C, exposed to the strongest magnetic field. In addition, DRG survival rate and nerve regeneration intensity were significantly higher in the C group. Above results indicate that strong spatial alternating magnetic field exerts positive effect on peripheral nerve regeneration and its application could be taken under consideration in the therapy of injured peripheral nerves. PMID:23781984

Suszy?ski, Krzysztof; Marcol, Wies?aw; Szajkowski, Sebastian; Pietrucha-Dutczak, Marita; Cie?lar, Grzegorz; Siero?, Aleksander; Lewin-Kowalik, Joanna

2014-09-01

193

Literature Review of Displacement Ventilation  

E-print Network

of Ventilated Rooms, Oslo, Norway. Nielsen, P.V., Hoff, L., Pedersen, L.G. 1988. Displacement Ventilation by Different Types of Diffusers. Proceedings of the 9 th AIVC Conference, Warwick. Niu, J. 1994. Modeling of Cooled-Ceiling Air-Conditioning Systems Ph... slender cylinder in a ventilated room. Proceedings of ROOMVENT ?90: International Conference on Engineergin Aero- and Thermodynamics of Ventilated Rooms, Oslo, Norway. This paper deals with some of the effects of persons present in a displacement...

Cho, S.; Im, P.; Haberl, J. S.

194

The association of octopamine with specific neurones along lobster nerve trunks.  

PubMed Central

Octapamine and its synthetic enzyme, tyramine beta-hydroxylase (TBH), are found in high concentrations at two points along second thoracic nerve roots in lobsters. The first is in the proximal section of the second root between the ventral nerve cord and the bifurcation of the root into medial (to flexor muscles) and lateral (to extensors) branches. The second region of high concentration is within a well known crustacean neurosecretory system, the pericardial organ, located close to the ends of the lateral branches of the roots. 2. With several different staining procedures, small clusters of nerve cell bodies are found within the connective tissue sheath in the proximal regions of the second roots. No cell bodies are seen in the pericardial organ regions. Cell bodies are variable in number and position between corresponding roots in the same animal and homologous roots among different animals. The average numbers of cell bodies, however, correlate well with TBH and octopamine content, and with the synthesis of octopamine in these same regions of roots. 3. Small clusters of root cell bodies dissected from preparations have greater than 500-fold higher activities of TBH than isolated efferent excitatory and inhibitory or afferent sensory axons. 4. Along with octopamine, the preferential synthesis of acetylcholine and serotonin is also seen in proximal segments of roots. Acetylcholine synthesis in these regions may represent transmitter synthesized in the nerve terminals innervating the root cells. The role of serotonin in these regions is not understood at this time but the amounts of endogenous serotonin found are only a tenth of the amounts of octopamine present. 5. Dopamine is not synthesized from tyrosine in second thoracic roots. However, if DOPA or dopamine are used as precursor compounds, then noradrenaline, which is usually not found in lobsters, can be accumulated in proximal segments of roots. 6. Phenolamines are converted to two further metabolites by lobster tissues. The compounds are unidentified and are named fast and slow product on the basis of their migration on electrophoresis at acid pH. Some partial characterization of slow product reveals that it is a mixture of compounds that can be converted on mild acid hydrolysis to fast product and the parent phenolamine. 7. The several lines of evidence presented suggest that nerve cells found in the proximal segments of the second thoracic roots contain and can synthesize octopamine. Since not all the cells in any single root have been analysed for octopamine or TBH, however, the possibility that one or more of the cells contain physiologically interesting substances other than octopamine is not eliminated. Images Plate 1 A B1, B2 C PMID:792417

Evans, P D; Kravitz, E A; Talamo, B R; Wallace, B G

1976-01-01

195

Ultrasound of Peripheral Nerves  

PubMed Central

Over the last decade, neuromuscular ultrasound has emerged as a useful tool for the diagnosis of peripheral nerve disorders. This article reviews sonographic findings of normal nerves including key quantitative ultrasound measurements that are helpful in the evaluation of focal and possibly generalized peripheral neuropathies. It also discusses several recent papers outlining the evidence base for the use of this technology, as well as new findings in compressive, traumatic, and generalized neuropathies. Ultrasound is well suited for use in electrodiagnostic laboratories where physicians, experienced in both the clinical evaluation of patients and the application of hands-on technology, can integrate findings from the patient’s history, physical examination, electrophysiological studies, and imaging for diagnosis and management. PMID:23314937

Suk, Jung Im; Walker, Francis O.; Cartwright, Michael S.

2013-01-01

196

Cranial Nerve II  

PubMed Central

This article contains a brief review of the anatomy of the visual system, a survey of diseases of the retina, optic nerve and lesions of the optic chiasm, and other visual field defects of special interest to the psychiatrist. It also includes a presentation of the corticothalamic mechanisms, differential diagnosis, and various manifestations of visual illusions, and simple and complex visual hallucinations, as well as the differential diagnoses of these various visual phenomena. PMID:19855858

Gillig, Paulette Marie; Sanders, Richard D.

2009-01-01

197

Peripheral Nerve Tumors  

Microsoft Academic Search

\\u000a Peripheral nerve tumors (PNTs) are rare soft tissue lesions that can arise anywhere on the body and as a result have a wide\\u000a differential diagnosis, which is often confirmed to be a PNT only at surgery. PNTs occur both sporadically and within the\\u000a context of genetically predisposing syndromes; hence, a thorough history of the mass and associated symptoms, with a

Joseph Wiley; Asis Kumar Bhattacharyya; Gelareh Zadeh; Patrick Shannon; Abhijit Guha

198

Peripheral nerve sheath tumor in a subadult golden eagle (Aquila chrysaetos).  

PubMed

A 5-year-old, female golden eagle (Aquila chrysaetos) was admitted with tetraplegia that progressed to a nonambulatory, spastic tetraparesis after a few days of treatment. Clinical and radiologic examinations, including radiography, computed tomography scan, and myelography, were indicative of neoplasia involving a spinal nerve root. Postmortem magnetic resonance imaging and necropsy findings confirmed the diagnosis of a peripheral nerve sheath neoplasia, not, to our knowledge, previously reported in a raptor. PMID:24881155

Wernick, Morena Bernadette; Dennler, Matthias; Beckmann, Kathrin; Schybli, Martina; Albini, Sarah; Hoop, Richard K; Steffen, Frank; Kircher, Patrick; Hatt, Jean-Michel

2014-03-01

199

Optic nerve hypoplasia  

PubMed Central

Optic nerve hypoplasia (ONH) is a congenital anomaly of the optic disc that might result in moderate to severe vision loss in children. With a vast number of cases now being reported, the rarity of ONH is obviously now refuted. The major aspects of ophthalmic evaluation of an infant with possible ONH are visual assessment, fundus examination, and visual electrophysiology. Characteristically, the disc is small, there is a peripapillary double-ring sign, vascular tortuosity, and thinning of the nerve fiber layer. A patient with ONH should be assessed for presence of neurologic, radiologic, and endocrine associations. There may be maternal associations like premature births, fetal alcohol syndrome, maternal diabetes. Systemic associations in the child include endocrine abnormalities, developmental delay, cerebral palsy, and seizures. Besides the hypoplastic optic nerve and chiasm, neuroimaging shows abnormalities in ventricles or white- or gray-matter development, septo-optic dysplasia, hydrocephalus, and corpus callosum abnormalities. There is a greater incidence of clinical neurologic abnormalities in patients with bilateral ONH (65%) than patients with unilateral ONH. We present a review on the available literature on the same to urge caution in our clinical practice when dealing with patients with ONH. Fundus photography, ocular coherence tomography, visual field testing, color vision evaluation, neuroimaging, endocrinology consultation with or without genetic testing are helpful in the diagnosis and management of ONH. (Method of search: MEDLINE, PUBMED). PMID:24082663

Kaur, Savleen; Jain, Sparshi; Sodhi, Harsimrat B. S.; Rastogi, Anju; Kamlesh

2013-01-01

200

Nanoliter Reactors Improve Multiple Displacement Amplification  

E-print Network

Nanoliter Reactors Improve Multiple Displacement Amplification of Genomes from Single Cells Yann) Nanoliter reactors improve multiple displacement amplification of genomes from single cells. PLoS Genet 3

Quake, Stephen R.

201

Near nerve potential of sural nerve in leprosy.  

PubMed

Leprosy neuropathy is characterized by initial involvement of the small nerve fibers, later followed by involvement of the large fibers, when routine nerve conduction studies become abnormal. To increase the diagnostic yield and precocity of these studies, we applied the near nerve technique to the sural nerve of 8 leprosy patients. Contrary to our expectations, the main component of the sural nerve sensory action potential was abnormal in all patients, but the minimum conduction velocity originating from small 3-6 mm fibers was normal or only mildly involved in three patients. Also, although Schwann cells are the first to be involved in leprosy, the results are suggestive of axonal degeneration instead of demyelination. To better understand the neurophysiology and physiology of leprosy and to increase the accuracy and precocity of the diagnosis, it will be necessary to investigate patients in the very early stages of the disease and to correlate these findings with the corresponding nerve pathology. PMID:15334210

Arruda, Ana Paula M; Marques, Wilson; Foss, Norma T; Garbino, José A; Virmond, Marcos; Barreira, Amilton A

2004-09-01

202

Nerve allografts and conduits in peripheral nerve repair.  

PubMed

Since the last update on nerve conduits and allograft in 2000, investigations have established the efficacy of these alternatives to autograft in the repair of small sensory neural gaps. However, limited insights into the biology of the regenerating nerve continue to preclude intelligent conduit design. Ongoing discoveries in neuroscience and biomaterial engineering hold promise for the eventual development of allograft and conduits with potential of surpassing nerve autografts in clinical efficacy. In this review, we summarize the history, recent advances, and emerging developments in nerve conduits and allograft. PMID:23895714

Lin, Michael Y; Manzano, Givenchy; Gupta, Ranjan

2013-08-01

203

Nitric oxide synthase, an essential factor in peripheral nerve regeneration.  

PubMed

Nitric oxide (NO) exerts both, pro-apoptotic and anti-apoptotic actions and appears to be acritical factor inneuronal degenerative and regenerative processes. NO is synthesized from L-arginine by NO synthase occurring in three isoforms of (neuronal, nNOS; endothelial, eNOS; inducible, iNOS). In a mice sciatic nerve model the regenerative outcome was assessed when the endogenous NO supply was deficient by knocking out the respective NOS isoform and compared to that of wild type mice after nerve transection. In nNOS knock-out mice a delay in regeneration, preceded by slowedWallerian degeneration and a disturbed pruning of uncontrolled sprouts, was observed. This was associated with a delayed recovery of sensory and motor function. Additionally, deficiency of nNOS led after nerve cut to a substantial loss of small and medium-sized dorsal root ganglia neurons, spinal cord interneurons and, to a lesser extent, spinal cord motor neurons. A lack of iNOS resulted in a delayed Wallerian degeneration and impaired regenerative outcome without consequences for neuronal survival. A lack of eNOS was well tolerated, although a delay in nerve revascularization was observed. Thus, after peripheral nerve lesion, regular NOS activity is essential for cell survival and recovery with reference to the nNOS isoform. PMID:14656046

Keilhoff, G; Fansa, H; Wolf, G

2003-09-01

204

Fibrolipoma of the median nerve.  

PubMed

Neural fibrolipoma or fibrolipomatous hamartoma is an uncommon benign tumor that usually arises in the median nerve. Fibrofatty tissue proliferates around the nerve and infiltrates the epineurium and perineurium. We report a case of fibrolipomatous hamartoma of the left median nerve in an 18-year-old woman. Our objective was to describe the pathognomonic magnetic resonance imaging features, whose presence obviates the need for a diagnostic biopsy. PMID:17178460

Nouira, Kais; Belhiba, Hend; Baccar, Sofiène; Miaaoui, Anissa; Ben Messaoud, Monia; Turki, Imène; Cheour, Ilhem; Menif, Emna

2007-01-01

205

Reduced Renshaw Recurrent Inhibition after Neonatal Sciatic Nerve Crush in Rats  

PubMed Central

Renshaw recurrent inhibition (RI) plays an important gated role in spinal motion circuit. Peripheral nerve injury is a common disease in clinic. Our current research was designed to investigate the change of the recurrent inhibitory function in the spinal cord after the peripheral nerve crush injury in neonatal rat. Sciatic nerve crush was performed on 5-day-old rat puppies and the recurrent inhibition between lateral gastrocnemius-soleus (LG-S) and medial gastrocnemius (MG) motor pools was assessed by conditioning monosynaptic reflexes (MSR) elicited from the sectioned dorsal roots and recorded either from the LG-S and MG nerves by antidromic stimulation of the synergist muscle nerve. Our results demonstrated that the MSR recorded from both LG-S or MG nerves had larger amplitude and longer latency after neonatal sciatic nerve crush. The RI in both LG-S and MG motoneuron pools was significantly reduced to virtual loss (15–20% of the normal RI size) even after a long recovery period upto 30 weeks after nerve crush. Further, the degree of the RI reduction after tibial nerve crush was much less than that after sciatic nerve crush indicatig that the neuron-muscle disconnection time is vital to the recovery of the spinal neuronal circuit function during reinnervation. In addition, sciatic nerve crush injury did not cause any spinal motor neuron loss but severally damaged peripheral muscle structure and function. In conclusion, our results suggest that peripheral nerve injury during neonatal early development period would cause a more sever spinal cord inhibitory circuit damage, particularly to the Renshaw recurrent inhibition pathway, which might be the target of neuroregeneration therapy. PMID:24778886

Shu, Liang; Su, Jingjing; Jing, Lingyan; Huang, Ying; Di, Yu; Peng, Lichao; Liu, Jianren

2014-01-01

206

A Novel CT-Guided Transpsoas Approach to Diagnostic Genitofemoral Nerve Block and Ablation  

PubMed Central

Background Inguinal hernia repair is associated with a high incidence of chronic postsurgical pain. This pain may be caused by injury to the iliohypogastric, ilioinguinal, or genitofemoral nerves. It is often difficult to identify the specific source of the pain, in part, because these nerves are derived from overlapping nerve roots and closely colocalize in the area of surgery. It is therefore technically difficult to selectively block these nerves individually proximal to the site of surgical injury. In particular, the genitofemoral nerve is retroperitoneal before entering the inguinal canal, a position that puts anterior approaches to the proximal nerve at risk of transgressing into the peritoneum. We report a computed tomography (CT)-guided transpsoas technique to selectively block the genitofemoral nerve for both diagnostic and therapeutic purposes while avoiding injury to the nearby ureter and intestines. Case A 39-year-old woman with chronic lancinating right groin pain after inguinal hernia repair underwent multiple pharmacologic interventions and invasive procedures without relief. Using CT and Stimuplex nerve stimulator guidance, the genitofemoral nerve was localized on the anterior surface of the psoas muscle and a diagnostic block with local anesthetic block was performed. The patient had immediate relief of her symptoms for 36 hours, confirming the diagnosis of genitofemoral neuralgia. She subsequently underwent CT-guided radiofrequency and phenol ablation of the genitofemoral nerve but has not achieved long-term analgesia. Conclusion CT-guided transpsoas genitofemoral nerve block is a viable option for safely and selectively blocking the genitofemoral nerve for diagnostic or therapeutic purposes proximal to injury caused by inguinal surgery. PMID:20546515

Parris, David; Fischbein, Nancy; Mackey, Sean; Carroll, Ian

2010-01-01

207

Dissecting Aneurysm of Vertebral Artery Manifestating as Contralateral Abducens Nerve Palsy  

PubMed Central

Isolated abducens nerve paresis related to ruptured vertebral artery (VA) aneurysm is rare. It usually occurs bilaterally or ipsilaterally to the pathologic lesions. We report the case of a contralateral sixth nerve palsy following ruptured dissecting VA aneurysm. A 38-year-old man was admitted for the evaluation of a 6-day history of headache. Abnormalities were not seen on initial computed tomography (CT). On admission, the patient was alert and no signs reflecting neurologic deficits were noted. Time of flight magnetic resonance angiography revealed a fusiform dilatation of the right VA involving origin of the posterior inferior cerebellar artery. The patient suddenly suffered from severe headache with diplopia the day before the scheduled cerebral angiography. Neurologic examination disclosed nuchal rigidity and isolated left abducens nerve palsy. Emergent CT scan showed high density in the basal and prepontine cistern compatible with ruptured aneurismal hemorrhage. Right vertebral angiography illustrated a right VA dissecting aneurysm with prominent displaced vertebrobasilar artery to inferiorly on left side. Double-stent placement was conducted for the treatment of ruptured dissecting VA aneurysm. No diffusion restriction signals were observed in follow-up magnetic resonance imaging of the brain stem. Eleven weeks later, full recovery of left sixth nerve palsy was documented photographically. In conclusion, isolated contralateral abducens nerve palsy associated with ruptured VA aneurysm may develop due to direct nerve compression by displaced verterobasilar artery triggered by primary thick clot in the prepontine cistern. PMID:23634273

Jeon, Jin Sue; Son, Young-Je; Chung, Young Seob

2013-01-01

208

In vivo nerve-macrophage interactions following peripheral nerve injury  

PubMed Central

In vertebrates, the peripheral nervous system has retained its regenerative capacity, enabling severed axons to reconnect with their original synaptic targets. While it is well documented that a favorable environment is critical for nerve regeneration, the complex cellular interactions between injured nerves with cells in their environment, as well as the functional significance of these interactions, have not been determined in vivo and in real time. Here we provide the first minute-by-minute account of cellular interactions between laser transected motor nerves and macrophages in live intact zebrafish. We show that macrophages arrive at the lesion site long before axon fragmentation, much earlier than previously thought. Moreover, we find that axon fragmentation triggers macrophage invasion into the nerve to engulf axonal debris, and that delaying nerve fragmentation in a Wlds model does not alter macrophage recruitment but induces a previously unknown ‘nerve scanning’ behavior, suggesting that macrophage recruitment and subsequent nerve invasion are controlled by separate mechanisms. Finally, we demonstrate that macrophage recruitment, thought to be dependent on Schwann cell derived signals, occurs independently of Schwann cells. Thus, live cell imaging defines novel cellular and functional interactions between injured nerves and immune cells. PMID:22423110

Rosenberg, Allison; Wolman, Marc A.; Franzini-Armstrong, Clara; Granato, Michael

2012-01-01

209

Environment-induced Population Displacements  

E-print Network

displacement / mobility related to environmental events Conceptual and methodological issues Climate change, security concerns and policy issues Based on IHDP OPEN MEETING 2009 The Social Challenges of Global Change) Adamo and De Sherbinin (forthcoming). The Impact of Climate Change on the Spatial Distribution

Columbia University

210

Stochastic Microgeometry for Displacement Mapping  

Microsoft Academic Search

Creating surfaces with intricate small-scale features (mi- crogeometry) and detail is an important task in geomet- ric modeling and computer graphics. We present a model processing method capable of producing a wide variety of complex surface features based on displacement mapping and stochastic geometry. The latter is a branch of mathe- matics that analyzes and characterizes the statistical prop- erties

Craig A. Schroeder; David E. Breen; Christopher D. Cera; William C. Regli

2005-01-01

211

Mass Media Displacement and Saturation  

Microsoft Academic Search

This study addresses the contradiction between the theoretical displacement of incumbent media by new media versus empirical evidence of rising consumption of both new and incumbent media. By analyzing 4 years of biannual daypart media consumption surveys, this research reveals trends in the consumer use of advertiser-supported media in the United States. Large gains were seen in new media, such

Jay Newell; Joseph J. Pilotta; John C. Thomas

2008-01-01

212

Tunnel-Effect Displacement Sensor  

NASA Technical Reports Server (NTRS)

Tunnel position sensor simple device measuring small displacements or accelerations. Used to make compact, sensitive accelerometers or strain gauges or to measure impacts of particles. Variation in distance between two electrodes measured via variation in tunneling current between them. Tunnel microsensors provide versatility for application as accelerometers, force sensors, strain sensors, particle detectors, and other devices for space applications.

Kaiser, William J.; Waltman, Steven B.

1989-01-01

213

Retraining Displaced Workers. Policy Brief  

ERIC Educational Resources Information Center

Robert LaLonde of the University of Chicago and Daniel Sullivan of the Federal Reserve Bank of Chicago suggest that retraining through our nation's community colleges is a way to reduce the skills gaps of at least some of these displaced workers and increase their reemployment earnings. Although workers may still experience significant earnings…

LaLonde, Robert; Sullivan, Daniel

2010-01-01

214

Polybenzimidazoles Via Aromatic Nucleophilic Displacement  

NASA Technical Reports Server (NTRS)

Soluble polybenzimidazoles (PBI's) synthesized by nucleophilic displacement reaction of di(hydroxyphenyl)-benzimidazole monomers with activated aromatic difluoride compounds in presence of anhydrous potassium carbonate. These polymers exhibit good thermal, thermo-oxidative, and chemical stability, and high mechanical properties. Using benzimidazole monomers, more economical, and new PBI's processed more easily than commercial PBI, without loss of desirable physical properties.

Connell, John W.; Hergenrother, Paul M.; Smith, Joseph G.

1994-01-01

215

Polyphenylquinoxalines Via Aromatic Nucleophilic Displacement  

NASA Technical Reports Server (NTRS)

Process for synthesis of polyphenylquinoxalines (PPQ's) involves nucleophilic displacement reactions of di(hydroxyphenyl) quinoxaline monomers with activated aromatic dihalides. New process costs less than other processes for synthesis of PPQ's. Facilitates synthesis of PPQ's of new and varied molecular structures. Useful as adhesives, coatings, films, membranes, and matrices for composites.

Hergenrother, Paul M.; Connell, John W.

1991-01-01

216

Roots and Shoots  

NSDL National Science Digital Library

In this outdoor activity, learners discover that plants aren't just shoots (stem, branches, leaves, and flowers) growing above ground, but contain plenty of roots growing undergroundâmore than half the mass of a plant can be its roots. Learners dig up "mystery" plants to investigate their root structures, and match them to different types of root systems. Learners also learn about animals found near plant roots and how humans use roots.

Science, Lawrence H.

2008-01-01

217

Diabetic Neuropathies: The Nerve Damage of Diabetes  

MedlinePLUS

... nerve damage to the bowels can cause constipation alternating with frequent, uncontrolled diarrhea, especially at night. Problems ... Nerve conduction studies check the transmission of electrical current through a nerve. Electromyography shows how well muscles ...

218

Character displacement in polyphenic tadpoles.  

PubMed

Biologists have long known that closely related species are often phenotypically different where they occur together, but are indistinguishable where they occur alone. The causes of such character displacement are controversial, however. We used polyphenic spadefoot toad tadpoles (Spea bombifrons and S. multiplicata) to test the hypothesis that character displacement evolves to minimize competition for food. We also sought to evaluate the role of phenotypic plasticity in the mediation of competitive interactions between these species. Depending on their diet, individuals of both species develop into either a small-headed omnivore morph, which feeds mostly on detritus, or a large-headed carnivore morph, which specializes on shrimp. Laboratory experiments and surveys of natural ponds revealed that the two species were more dissimilar in their tendency to produce carnivores when they occurred together than when they occurred alone. This divergence in carnivore production was expressed as both character displacement (where S. multiplicata's propensity to produce carnivores was lower in sympatry than in allopatry) and as phenotypic plasticity (where S. multiplicata facultatively enhanced carnivore production in S. bombifrons, and S. bombifrons facultatively suppressed carnivore production in S. multiplicata). In separate experiments, we established that S. bombifrons (the species for which carnivore production was enhanced) was the superior competitor for shrimp. Conversely, S. multiplicata (the species for which carnivore production was suppressed and omnivore production enhanced) was the superior competitor for detritus. These results therefore demonstrate that selection to minimize competition for food can cause character displacement. They also suggest that both character displacement and phenotypic plasticity may mediate competitive interactions between species. PMID:11108600

Pfennig, D W; Murphy, P J

2000-10-01

219

The loss of antinociceptive efficacy of spinal morphine in rats with nerve ligation injury is prevented by reducing spinal afferent drive  

Microsoft Academic Search

Nerve ligation injury in rats may represent a useful model of some clinical neuropathic pains. Activation of N-methyl-d-aspartate (NMDA) receptors may maintain central sensitivity and contribute to neuropathic pain. Here, nerve injury was produced by unilateral ligation of the L5 and L6 spinal roots of the sciatic nerve of rats. Catheters were inserted for intrathecal (i.th.) or local delivery of

Michael H. Ossipov; Yvan Lopez; Michael L. Nichols; Di Bian; Frank Porreca

1995-01-01

220

Bilateral optic nerve hypoplasia.  

PubMed

In the past 10 years, 15 children with bilateral optic nerve hypoplasia have been studied at the Royal Alexandra Hospital for Children. There were 5 boys and 10 girls. Nine were first-born and they presented at a mean age of 5 months (range: 4 days to 25 months). Five presented with suspected blindness and 7 with abnormal eye movements (nystagmus or less commonly squint). The other 3 presented because of fits or developmental delay. Eight showed evidence of neural damage--microcephaly, seizures and/or abnormalities of tone. Four appeared to be of normal or near normal intelligence, 6 were mildly retarded and 5 severely so. Two patients had already died, one suddenly. Six of the 7 cases investigated in detail had evidence of hypothalamic pituitary dysfunction. Another one had a minimal hypothalamic abnormality. Four were severely growth retarded and 2 were receiving growth hormone replacement. Two males had micropenis and a girl had precocious puberty with partial diabetes insipidus. Neuroradiological investigations showed an absent septum pellucidum in only 5 cases. Five patients had other major CNS malformations. Five patients had normal CT scans; 3 of these 5 appeared of normal intelligence and all 5 had normal neurological examinations. Bilateral optic nerve hypoplasia is frequently associated with serious brain and endocrine abnormalities. PMID:6926392

Ouvrier, R A; Lewis, D; Procopis, P G; Billson, F A; Silink, M; de Silva, M

1981-01-01

221

Temporal Adaptation Silicon Auditory Nerve  

E-print Network

Temporal Adaptation in a Silicon Auditory Nerve John Lazzaro CS Division UC Berkeley 571 Evans Hall (bottom trace), we see the envelope of the temporal adaptation superimposed on the cycle-by-cycle phase-locking). In biological auditory nerve fibers, cycle-by-cycle phase locking ceases for auditory fibers tuned

Lazzaro, John

222

Functions of the Renal Nerves.  

ERIC Educational Resources Information Center

Discusses renal neuroanatomy, renal vasculature, renal tubules, renin secretion, renorenal reflexes, and hypertension as related to renal nerve functions. Indicates that high intensitites of renal nerve stimulation have produced alterations in several renal functions. (A chart with various stimulations and resultant renal functions and 10-item,…

Koepke, John P.; DiBona, Gerald F.

1985-01-01

223

Regional Aggressive Root Resorption Caused by Neuronal Virus Infection  

PubMed Central

During orthodontic treatment, root resorption can occur unexplainably. No clear distinction has been made between resorption located within specific regions and resorption occurring generally in the dentition. The purpose is to present cases with idiopathic (of unknown origin) root resorption occurring regionally. Two cases of female patients, 26 and 28 years old, referred with aggressive root resorption were investigated clinically and radiographically. Anamnestic information revealed severe virus diseases during childhood, meningitis in one case and whooping cough in the other. One of the patients was treated with dental implants. Virus spreading along nerve paths is a possible explanation for the unexpected resorptions. In both cases, the resorptions began cervically. The extent of the resorption processes in the dentition followed the virus infected nerve paths and the resorption process stopped when reaching regions that were innervated differently and not infected by virus. In one case, histological examination revealed multinuclear dentinoclasts. The pattern of resorption in the two cases indicates that innervation is a factor, which under normal conditions may protect the root surface against resorption. Therefore, the normal nerve pattern is important for diagnostics and for predicting the course of severe unexpected root resorption. PMID:23097724

Kjaer, Inger; Str?m, Carsten; Worsaae, Nils

2012-01-01

224

Peripheral nerve lengthening as a regenerative strategy  

PubMed Central

Peripheral nerve injury impairs motor, sensory, and autonomic function, incurring substantial financial costs and diminished quality of life. For large nerve gaps, proximal lesions, or chronic nerve injury, the prognosis for recovery is particularly poor, even with autografts, the current gold standard for treating small to moderate nerve gaps. In vivo elongation of intact proximal stumps towards the injured distal stumps of severed peripheral nerves may offer a promising new strategy to treat nerve injury. This review describes several nerve lengthening strategies, including a novel internal fixator device that enables rapid and distal reconnection of proximal and distal nerve stumps.

Vaz, Kenneth M.; Brown, Justin M.; Shah, Sameer B.

2014-01-01

225

Peripheral nerve surgery: primer for the imagers.  

PubMed

Peripheral nerve surgery represents a broad field of pathologic conditions, medical specialties, and anatomic regions of the body. Anatomic understanding of hierarchical nerve structure and the peripheral nervous system aids diagnosis and management of nerve lesions. Many peripheral nerves coalesce into organized arrays, including the cervical, brachial, and lumbosacral plexuses, controlling motor and sensory functions of the trunk and extremities. Individual or groups of nerves may be affected by various pathologic conditions, including trauma, entrapment, tumor, or iatrogenic damage. Current research efforts focus on enhancing the peripheral nerve regenerative process by targeting Schwann cells, nerve growth factors, and nerve allografts. PMID:24210320

Pindrik, Jonathan; Belzberg, Allan J

2014-02-01

226

Local and remote immune-mediated inflammation after mild peripheral nerve compression in rats.  

PubMed

After experimental nerve injuries that extensively disrupt axons, such as chronic constriction injury, immune cells invade the nerve, related dorsal root ganglia (DRGs), and spinal cord, leading to hyperexcitability, raised sensitivity, and pain. Entrapment neuropathies, such as carpal tunnel syndrome, involve minimal axon damage, but patients often report widespread symptoms. To understand the underlying pathology, a tube was placed around the sciatic nerve in 8-week-old rats, leading to progressive mild compression as the animals grew. Immunofluorescence was used to examine myelin and axonal integrity, glia, macrophages, and T lymphocytes in the nerve, L5 DRGs, and spinal cord after 12 weeks. Tubes that did not constrict the nerve when applied caused extensive and ongoing loss of myelin, together with compromise of small-, but not large-, diameter axons. Macrophages and T lymphocytes infiltrated the nerve and DRGs. Activated glia proliferated in DRGs but not in spinal cord. Histologic findings were supported by clinical hyperalgesia to blunt pressure and cold allodynia. Tubes that did not compress the nerve induced only minor local inflammation. Thus, progressive mild nerve compression resulted in chronic local and remote immune-mediated inflammation depending on the degree of compression. Such neuroinflammation may explain the widespread symptoms in patients with entrapment neuropathies. PMID:23771220

Schmid, Annina B; Coppieters, Michel W; Ruitenberg, Marc J; McLachlan, Elspeth M

2013-07-01

227

Force transmissibility versus displacement transmissibility  

NASA Astrophysics Data System (ADS)

It is well-known that when a single-degree-of-freedom (sdof) system is excited by a continuous motion of the foundation, the force transmissibility, relating the force transmitted to the foundation to the applied force, equals the displacement transmissibility. Recent developments in the generalization of the transmissibility to multiple-degree-of-freedom (mdof) systems have shown that similar simple and direct relations between both types of transmissibility do not appear naturally from the definitions, as happens in the sdof case. In this paper, the authors present their studies on the conditions under which it is possible to establish a relation between force transmissibility and displacement transmissibility for mdof systems. As far as the authors are aware, such a relation is not currently found in the literature, which is justified by being based on recent developments in the transmissibility concept for mdof systems. Indeed, it does not appear naturally, but the authors observed that the needed link is present when the displacement transmissibility is obtained between the same coordinates where the applied and reaction forces are considered in the force transmissibility case; this implies that the boundary conditions are not exactly the same and instead follow some rules. This work presents a formal derivation of the explicit relation between the force and displacement transmissibilities for mdof systems, and discusses its potential and limitations. The authors show that it is possible to obtain the displacement transmissibility from measured forces, and the force transmissibility from measured displacements, opening new perspectives, for example, in the identification of applied or transmitted forces. With this novel relation, it becomes possible, for example, to estimate the force transmissibility matrix with the structure off its supports, in free boundary conditions, and without measuring the forces. As far as force identification is concerned, this novel approach significantly decreases the computational effort when compared to conventional approaches, as it requires only local information of the sets of coordinates involved. Numerical simulations and experimental examples are presented and discussed, to illustrate the proposed developments.

Lage, Y. E.; Neves, M. M.; Maia, N. M. M.; Tcherniak, D.

2014-10-01

228

Photofabricated gelatin-based nerve conduits: nerve tissue regeneration potentials.  

PubMed

There is a strong demand for development of nerve guide conduit with prompt nerve regeneration potential for injury-induced nerve defect. Prior to study on nerve tissue engineering using Schwann cells or nerve stem cells, the effectiveness of photofabricated scaffolds based on photocurable gelatin was examined. This study describes the evaluation of in vivo nerve tissue regeneration potentials of three custom-designed and -fabricated prostheses (inner diameter, 1.2 mm; outer diameter, 2.4 mm; wall thickness, 0.60 mm; and length, 15 mm) made of photocured gelatin: a plain photocured gelatin tube (model I), a photocured gelatin tube packed with bioactive substances (laminin, fibronectin, and nerve growth factor) coimmobilized in a photocured gelatin rod (model II), and a photocured gelatin tube packed with bioactive substances coimmobilized in multifilament fibers (model III). These prostheses were implanted between the proximal and distal stumps 10 mm of the dissected right sciatic nerve of 70 adult male Lewis rats for up to 1 year. The highest regenerative potentials were found using the model III prosthesis, followed by the model II prosthesis. Markedly retarded neural regeneration was observed using the model I prosthesis. These were evaluated from the viewpoints of functional recovery, electrophysiological responses, and tissue morphological regeneration. The significance of the synergistic cooperative functions of multifilaments, which serve as a platform that provides contact guidance to direct longitudinal cell movement and tissue ingrowth and as a cell adhesive matrix with high surface area, and immobilized bioactive substances, which enhance nerve regeneration via biological stimulation, is discussed. PMID:15565867

Gámez, Eduardo; Goto, Yoshinobu; Nagata, Kengo; Iwaki, Toru; Sasaki, Tomio; Matsuda, Takehisa

2004-01-01

229

Fiber optic multimode displacement sensor  

Microsoft Academic Search

An underwater Optical Motion Sensor (OMS) based on a design first presented by W. B. Spillman, Schlieren multimode fiber-optic hydrophone, Applied Physics Letters 37(2), 15 July 1980, p. 145-146 is described. The displacement sensor uses the same acoustooptical intensity modulation mechanism as Spillman, however the sensing mechanism is isolated from the ambient fluid environment by a small cylindrical aluminum enclosure

Karl A. Fisher; Jacek Jarzynski

1996-01-01

230

Polyphenylquinoxalines via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

Polyphenylquinoxalines are prepared by the nucleophilic displacement reaction of di(hydroxyphenyl)quinoxaline monomers with activated aromatic dihalides or dinitro compounds. The reactions are carried out in polar aprotic solvents using alkali metal bases at elevated temperatures under nitrogen. The di(hydroxyphenyl)quinoxaline monomers are prepared either by reacting stoichiometric quantities of aromatic bis(o-diamines) with a hydroxybenzil or by reacting o-phenylenediamine with a dihydroxybenzil or bis(hydroxyphenylglyoxylyl)benzene.

Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor)

1990-01-01

231

Knowledge integration and displaced volume  

NSDL National Science Digital Library

This study contrasted spontaneous and reflective knowledge integration instruction delivered using a computer learning environment to enhance understanding of displaced volume. Both forms of instruction provided animated experiments and required students to predict outcomes, observe results, and explain their ideas. In addition, the reflective instruction diagnosed specific inconsistencies in student reasoning and encouraged students to reflect on these dilemmas as well as to construct general principles. We distinguished the impact of instruction on students who believed scientific phenomena are governed by principles (cohesive beliefs) versus students who believed that science is a collection of unrelated ldquofactsrdquo (dissociated beliefs). Students typically held multiple models of displacement, using different explanations depending on the form of assessment. For example, we found that 17% of these middle school students made accurate predictions about displacement experiments prior to instruction and 25% could construct an accurate general principle. However, only 12% consistently used the same explanation across assessments. After instruction, students were more accurate and more consistent: over 50% accurately predicted experimental outcomes, 79% gave an accurate general principle, and about 40% gave consistent responses. We found no advantages for enhanced animations over straightforward animated experiments. The reflective integration instruction led to more substantial long-term changes in student understanding than did spontaneous integration instruction. Furthermore, on a delayed posttest we found that students with cohesive beliefs not only sustained their understanding of displaced volume, but, when exposed to reflective integration instruction, actually continued to construct more predictive views following instruction. In contrast, students with dissociated beliefs made no long-term progress independent of the form of instruction.

Linn, Marcia; Eylon, Bat-Sheva

2006-12-07

232

Coupled diffusional/displacive transformations  

E-print Network

COUPLED DIFFUSIONAL/DISPLACIVE TRANSFORMATIONS Shafiq Ahmad Mujahid Darwin College Cambridge A dissertation submitted for the degree of Doctor of Philosophy at the University of Cambridge July 1992 Dedicated to my parents, Saif-ur-Rehman and Mariam... of plate-shaped particle) and dislocation- interface velocity versus interfacial dissipation, identifying stable steady-state velocity for the coupled process. 14 2.2 The Response Functions It is necessary to solve for three unknowns: the carbon...

Mujahid, Shafiq Ahmad

233

Polyphenylquinoxalines via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

Polyphenylquinoxalines are prepared by the nucleophilic displacement reaction of di(hydroxyphenyl)quinoxaline monomers with activated aromatic dihalides or dinitro compounds. The reactions are carried out in polar aprotic solvents during alkali metal bases at elevated temperatures under nitrogen. The di(hydroxyphenyl)quinoxaline monomers are prepared either by reacting stoichiometric quantities of aromatic bis(o-diamines) with a hydroxybenzil or by reacting o-phenylenediamine with a dihydroxybenzil or bis(hydroxyphenylglyoxylyl)benzene.

Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor)

1991-01-01

234

ON THE ORIGINS OF DORSAL ROOT POTENTIALS  

PubMed Central

The "dorsal root potential" consists of five successive deflections designated for convenience, D.R.I, II, III, IV, and V. Of these, D.R.V alone constitutes the dorsal root potential of prior description. A study has been made of the general properties of those deflections not previously described. Dorsal root potentials are electrotonic extensions into the extramedullary root segment, the result of electrical interactions within the cord comparable to those that have been studied in peripheral nerve. Although the anatomical and electrical conditions of interaction are infinitely more complex in the cord than in nerve, it is seen that the fact of parallel distribution of primary afferent fibers pertaining to neighboring dorsal roots provides a sufficient anatomical basis for qualitative analysis in the first approximation of dorsal root potentials. An extension of the theory of interaction between neighboring nerve fibers has been made to include an especial case of interaction between fibers orientated at right angles to one another. The predictions have been tested in a nerve model and found correct. Given this elaboration, and the stated anatomical propositions, existing knowledge of interaction provides an adequate theoretical basis for an elementary understanding of dorsal root potentials. The study of general properties and the analysis of dorsal root potentials have led to the formulation of certain conclusions that follow. D.R.I, II, and III record the electrotonic spread of polarization resulting from the external field of impulses conducted in the intramedullary segment and longitudinal trajects of primary afferent fibers. D.R.IV arises in part as the result of activity in primary afferent fibers, and in part as the result of activity in secondary neurons. In either case the mode of production is the same, and the responsible agent is residual negativity in the active collaterals, or, more precisely, the external field of current flow about the collaterals during the period of residual negativity. Current flow about active primary afferent collaterals during the period of residual negativity is the agent for residual facilitation of monosynaptic reflex pathways. Since the changes in reflex threshold follow the course of residual negativity there is no need to postulate especial properties for prolonging action at regions the threshold of which is measured by means of monosynaptic test reflexes. D.R.V results from polarization of primary afferent fibers by current flow about secondary neurons. There is indication that somata rather than axons of secondary neurons generate the polarizing currents. Similarity between D.R.V and the positive intermediary potential further indicates that soma gradients established during the recovery cycle are responsible for D.R.V. Little or no net polarization of primary afferent fibers results from activity confined to the contralateral gray substance, the dorsal root potentials in contralateral recording resulting from interaction in the dorsal column or in the ipsilateral gray substance following decussation of contralaterally evoked activity. During the course of asphyxia the initial defect in reflex pathways is the failure of secondary neurons to respond to primary impulses. Subsequently block is established at the branching zone of primary afferent fibers. A relation exists between the sequence of dorsal root potentials and the cord potential sequence, the major departure from exact correspondence occurring in the region of D.R.IV and the negative intermediary potential and being of a nature to suggest that different aspects of internuncial activity are emphasized by the two methods of leading. PMID:18114558

Lloyd, David P. C.; McIntyre, A. K.

1949-01-01

235

Conversion of high sacral to midsacral amputation via S-2 nerve preservation during partial S-2 sacrectomy for chordoma.  

PubMed

Chordomas of the sacrum require en bloc resection to reduce the risk of recurrence, but this may sacrifice nerves vital to bladder, bowel, and sexual function. High, mid-, and low sacral amputations have been previously classified based on nerve root sacrifice, not bony amputation. Sacrifice of the S-2 nerves or those above results in a high sacral amputation, but preserving the S-2 nerves converts it into a midsacral amputation. Preservation of the S-2 nerves has been shown to improve functional outcome, despite the bony osteotomy being unchanged. Thus, keeping the same bony amputation while preserving the S-2 nerve roots may allow for improved functional outcome while still achieving the same goal of oncological resection. Preservation of the S-2 nerves may be particularly difficult during amputation at the S-2 pedicle or above, and the authors describe their technique for preserving the S-2 nerves during partial sacrectomy at or just above the S-2 pedicle. Four cases of sacral chordoma resections are presented to illustrate the technique. PMID:24527829

Saigal, Rajiv; Lu, Daniel C; Deng, Donna Y; Chou, Dean

2014-04-01

236

Peripheral nerve regeneration with sustained release of poly(phosphoester) microencapsulated nerve growth factor within nerve guide conduits  

Microsoft Academic Search

Prolonged delivery of neurotrophic proteins to the target tissue is valuable in the treatment of various disorders of the nervous system. We have tested in this study whether sustained release of nerve growth factor (NGF) within nerve guide conduits (NGCs), a device used to repair injured nerves, would augment peripheral nerve regeneration. NGF-containing polymeric microspheres fabricated from a biodegradable poly(phosphoester)

Xiaoyun Xu; Woon-Chee Yee; Peter Y. K Hwang; Hanry Yu; Andrew C. A Wan; Shujun Gao; Kum-Loong Boon; Hai-Quan Mao; Kam W Leong; Shu Wang

2003-01-01

237

Gravitropic curvature of maize roots is not preceded by rootcap asymmetry  

NASA Technical Reports Server (NTRS)

We tested whether the first response to gravistimulation is an asymmetry in the root tip that results from differential growth of the rootcap itself. The displacement of markers on the rootcap surface of maize (Zea mays L. cv. Merit) roots was quantified from videotaped images using customized software. The method was sensitive enough to detect marker displacements down to 15 microns and root curvature as early as 8 min after gravistimulation. No differential growth of the upper and lower sides of the cap occurred before or during root curvature. Fewer than a third of all gravistimulated roots developed an asymmetrical outline of the root tip after curvature had started, and this asymmetry did not occur in the rootcap itself. Our data support the view that the regions of gravitropic sensing and curvature are spatially separate during all phases of gravitropism in maize roots.

Sack, F. D.; Hasenstein, K. H.; Blair, A.

1990-01-01

238

Investigation of cranial and other nerves in the mouse with muscular dystrophy.  

PubMed Central

In the muscular dystrophic mouse mutant there is an absence of Schwann cells over circumscribed lengths of all cranial nerves except for II (I was not examined) and the lesion involves the sympathetic system. Where present, Schwann cells do not produce myelin of normal thickness. The lesion is similar to that described for the spinal roots. Causation is discussed. Images PMID:1141926

Biscoe, T J; Caddy, K W; Pallot, D J; Pehrson, U M

1975-01-01

239

Octopamine release at two points along lobster nerve trunks.  

PubMed Central

Nerve cells in the proximal regions of second thoracic roots in lobsters have been injected with the fluorescent dye Procion Yellow. Examination of the roots reveals an elaborate array of cell branches in a superficial layer of the root in the vicinity of the cell bodies. Large varicosities, up to 10 mum in diameter, are seen lined up along fine nerve branches. 2. In these same regions, electron microscopic examination shows the presence of large profiles filled with 0-1-0-2 mum dense cored granules, and having the appearance of nerve endings. These profiles probably correspond to the varicosities seen in the Procion Yellow injections. The dense cored granules within the endings have a crystalline substructure. All the endings are found within 7 mum of the surface of the root and no obvious physiological target tissue exists in their surroundings. Endings have not been traced directly to root cell bodies.However, granules of similar dimensions to those seen in endings are found in cell bodies, axon-hillock regions and numerous axonal profiles in the superficial root regions near cell bodies. The morphological studies suggest that the root neurones have the typical appearance of neurosecretory cells. 3. Octopamine pools in cell body regions of second thoracic roots can be isotopically labelled by incubation with either [3H]tyramine or [3H]-tyrosine. After labelling, pulsing with 100 mM potassium causes an increase in the rate of release of radioactive material. Upon return to normal media background rates of release are re-established. The enhanced efflux has the following properties: (a) repeated pulses of potassium release less radio-active material each time; (b) a prolonged potassium pulse produces first a peak of release, then a decline to a plateau, and the plateau level of release is maintained for the duration of the potassium pulse; (c) release is dependent on the presence of calcium ions in the bathing fluid and 40 mM cobalt prevents release; (d) release is selective for octopamine. With tyrosine as a precursor compound, as much radioactive tyrosine as octopamine is found in tissues after incubation, yet pulsing with potassium causes an enhanced efflux only of octopamine from preparations. 4. Release of octopamine also can be demonstrated from pericardial organs near the ends of lateral branches of the roots and the properties of the release are identical to those seen with cell body regions. 5. Physiological studies, in which root cells are antidromically activated while recording from cell bodies, suggest that the distal endings of at least some of the root cells are at the pericardial organs. 6. The results suggest that root cell neurones are neurosecretory cells capable of releasing octopamine at two points: one near cell bodies, the other at the pericardial organs near the distal ends of the roots... Images Plate 1 A B C PMID:792418

Evans, P D; Kravitz, E A; Talamo, B R

1976-01-01

240

Brainstem abnormalities and vestibular nerve enhancement in acute Neuroborreliosis  

PubMed Central

Background Borreliosis is a widely distributed disease. Neuroborreliosis may present with unspecific symptoms and signs and often remains difficult to diagnose in patients with central nervous system symptoms, particularly if the pathognomonic erythema chronica migrans does not develop or is missed. Thus, vigilance is mandatory in cases with atypical presentation of the disease and with potentially severe consequences if not recognized early. We present a patient with neuroborreliosis demonstrating brain stem and vestibular nerve abnormalities on magnetic resonance imaging. Case presentation A 28-year-old Caucasian female presented with headaches, neck stiffness, weight loss, nausea, tremor, and gait disturbance. Magnetic resonance imaging showed T2-weighted hyperintense signal alterations in the pons and in the vestibular nerves as well as bilateral post-contrast enhancement of the vestibular nerves. Serologic testing of the cerebrospinal fluid revealed the diagnosis of neuroborreliosis. Conclusion Patients infected with neuroborreliosis may present with unspecific neurologic symptoms and magnetic resonance imaging as a noninvasive imaging tool showing signal abnormalities in the brain stem and nerve root enhancement may help in establishing the diagnosis. PMID:24359885

2013-01-01

241

Gravisensing in flax roots - results from STS-107  

NASA Astrophysics Data System (ADS)

The goal of the experiment "magnetophoretic induction of curvature in roots" (MICRO) on STS-107 was the induction of curvature in roots by high-gradient magnetic fields (HGMF) in microgravity. The scientific objectives included investigating the growth/curvature pattern in response to a HGMF, the determination of amyloplasts as gravisensing/curvature-inducing structures, and a study of the effects of HGMF and microgravity on the plant cytoskeleton. Flax seeds were germinated in orbit in specially designed seed cassettes. The seeds were oriented so that the emerging roots grew away from the cassette. The magnetic system consisted of ferro-magnetic wedges, magnetized by permanent NdFeB magnets (coercivity > 32k Oe). The HGMF that results from the transition from the high magnetic field density at the wedge tips to air repels diamagnetic amyloplasts. As a result of the previously demonstrated internal displacement of the amyloplasts, the roots were expected to curve as if gravistimulated. Despite successful germination (>90%), the growth rate of the seedlings was significantly lower than comparable controls. Despite the slower growth rate, root curvature was enhanced and initiated earlier than in ground controls. The results indicate that microgravity-grown roots exhibit higher sensitivity for the HGMF than ground controls. The enhanced sensitivity of root curvature in microgravity suggests that the root gravisensing system responds to the displacement of amyloplasts. In the absence of gravity, the higher sensitivity might result from intracellular motion, which in microgravity is likely to be stronger than on the ground.

Hasenstein, K. H.; Scherp, P.; Ma, Z.

242

Endometriotic lesions of the lower troncular nerves.  

PubMed

Although exceptional, endometriotic lesions of the troncular nerves of the lower limb may occur and are often diagnosed with delay. We report, hereby, the first case of femoral nerve endometriosis the treatment of which consisted of radical resection with femoral nerve transplant. We completed a review of the literature on sciatic nerve endometriotic lesions and discussed the physiopathology and surgical treatment. PMID:25267476

Niro, J; Fournier, M; Oberlin, C; Le Tohic, A; Panel, P

2014-10-01

243

Mechanisms of Nerve Damage in Leprosy  

Microsoft Academic Search

Peripheral nerve involvement is inevitable once infection progresses to disease in man with leprosy. Some of the relevant questions pertaining to mechanisms of nerve damage in leprosy are: How does M. leprae gain entry into the nerve? What is the sequence of events that follow? How early and diffused is the nerve involvement? What is the relationship between infection, inflammation

V. P. Shetty

244

Local interpolation of coseismic displacements measured by InSAR  

NASA Astrophysics Data System (ADS)

Coseismic displacements play a significant role in characterizing earthquake causative faults and understanding earthquake dynamics. They are typically measured from InSAR using pre- and post-earthquake images. The displacement map produced by InSAR may contain missing coseismic values due to the decorrelation of ASAR images. This study focused on interpolating missing values in the coseismic displacement map of the 2003 Bam earthquake using geostatistics with the aim of running a slip distribution model. The gaps were grouped into 23 patches. Variograms of the patches showed that the displacement data were spatially correlated. The variogram prepared for ordinary kriging (OK) indicated the presence of a trend and thus justified the use of universal kriging (UK). Accuracy assessment was performed in 3 ways. First, 11 patches of equal size and with an equal number of missing values generated artificially, were kriged and validated. Second, the four selected patches results were validated after shifting them to new locations without missing values and comparing them with the observed values. Finally, cross validation was performed for both types of patch at the original and shifted locations. UK results were better than OK in terms of kriging variance, mean error (ME) and root mean square error (RMSE). For both OK and UK, only 4 out of 23 patches (1, 5, 11 and 21) showed ME and RMSE values that were substantially larger than for the other patches. The accuracy assessment results were found to be satisfactory with ME and RMSE values close to zero. InSAR data inversion demonstrated the usefulness of interpolation of the missing coseismic values by improving a slip distribution model. It is therefore concluded that kriging serves as an effective tool for interpolating the missing values on a coseismic displacement map.

Yaseen, M.; Hamm, N. A. S.; Woldai, T.; Tolpekin, V. A.; Stein, A.

2013-08-01

245

The neglected cranial nerve: nervus terminalis (cranial nerve N).  

PubMed

The nervus terminalis (NT; terminal nerve) was clearly identified as an additional cranial nerve in humans more than a century ago yet remains mostly undescribed in modern anatomy textbooks. The nerve is referred to as the nervus terminalis because in species initially examined its fibers were seen entering the brain in the region of the lamina terminalis. It has also been referred to as cranial nerve 0, but because there is no Roman symbol for zero, an N for the Latin word nulla is a better numerical designation. This nerve is very distinct in human fetuses and infants but also has been repeatedly identified in adult human brains. The NT fibers are unmyelinated and emanate from ganglia. The fibers pass through the cribriform plate medial to those of the olfactory nerve fila. The fibers end in the nasal mucosa and probably arise from autonomic/neuromodulatory as well as sensory neurons. The NT has been demonstrated to release luteinizing-releasing luteinizing hormone and is therefore thought to play a role in reproductive behavior. Based on the available evidence, the NT appears to be functional in adult humans and should be taught in medical schools and incorporated into anatomy/neuroanatomy textbooks. PMID:22836597

Vilensky, Joel A

2014-01-01

246

An anatomical analysis of the dorsoventral relationship between the sacral plexus and the pudendal nerve in man by use of computer aided three-dimensional reconstruction.  

PubMed

In order to investigate the dorsoventral relationship between the sacral plexus and the pudendal nerve in man, morphological examination was performed on one pelvic half of a male cadaver. The second and third spinal nerves were removed en bloc and sectioned serially for three-dimensional reconstruction imaging of the selected sections. Comparison of the sequential images revealed that the root of the pudendal nerve is first situated ventral to the caudal root of the sacral plexus, and that the former and the latter are shifted cranialward and caudalward, respectively, at the point of exit from the second anterior sacral foramen. PMID:7566877

Akita, K; Yamamoto, H

1995-05-01

247

Water Mist Suppression in Conjunction with Displacement  

E-print Network

Water Mist Suppression in Conjunction with Displacement Ventilation By Benjamin Piers Hume-2758 #12;#12;Displacement Water Mist System Masters of Fire Engineering Thesis 2003 i A man of genius makes Water Mist System Masters of Fire Engineering Thesis 2003 ii #12;Displacement Water Mist System Masters

Hickman, Mark

248

Burglary Reduction and the Myth of Displacement  

Microsoft Academic Search

Burglary remains a significant crime problem across Australia. While the Australian Institute of Criminology is keen to encourage burglary reduction initiatives, it often encounters the view that targeted operations simply displace crime to another area. This perception of total crime displacement is common, but has no strong evidential basis. While some studies have measured a modest degree of displacement in

Jerry Ratcliffe

2002-01-01

249

Displacement, Space and Dwelling: Placing Gentrification Debate  

Microsoft Academic Search

This paper is concerned with the conceptualisations of space which underlie debate of gentrification-related displacement. Using Derrida's concept of the spatial metaphor, the paper illuminates the Cartesian understandings of space that act as architecture for displacement debate. The paper corrects this through arguing that the philosophy of Heidegger and Lefebvre better serves to understand displacement. Emphasising the topology of Heidegger's

Mark Davidson

2009-01-01

250

Displacement Compensation of Temperature Probe Data  

NASA Technical Reports Server (NTRS)

Analysis of temperature data from a probe in a vertical Bridgman furnace growing germanium crystals revealed a displacement of the temperature profile due to conduction error. A theoretical analysis shows that the displacement compensation is independent of local temperature gradient. A displacement compensation value should become a standard characteristic of temperature probes used for temperature profile measurements.

Welch, Christopher S.; Hubert, James A.; Barber, Patrick G.

1996-01-01

251

Imaging of the facial nerve.  

PubMed

The facial nerve is responsible for the motor innervation of the face. It has a visceral motor function (lacrimal, submandibular, sublingual glands and secretion of the nose); it conveys a great part of the taste fibers, participates to the general sensory of the auricle (skin of the concha) and the wall of the external auditory meatus. The facial mimic, production of tears, nasal flow and salivation all depend on the facial nerve. In order to image the facial nerve it is mandatory to be knowledgeable about its normal anatomy including the course of its efferent and afferent fibers and about relevant technical considerations regarding CT and MR to be able to achieve high-resolution images of the nerve. PMID:20456888

Veillona, F; Ramos-Taboada, L; Abu-Eid, M; Charpiot, A; Riehm, S

2010-05-01

252

Sciatic nerve regeneration is not inhibited by anti-NGF antibody treatment in the adult rat.  

PubMed

Elevated nerve growth factor (NGF) is believed to play a role in many types of pain. An NGF-blocking antibody (muMab 911) has been shown to reduce pain and hyperalgesia in pain models, suggesting a novel therapeutic approach for pain management. Since NGF also plays important roles in peripheral nervous system development and sensory nerve outgrowth, we asked whether anti-NGF antibodies would adversely impact peripheral nerve regeneration. Adult rats underwent a unilateral sciatic nerve crush to transect axons and were subcutaneously dosed weekly for 8weeks with muMab 911 or vehicle beginning 1day prior to injury. Plasma levels of muMab 911 were assessed from blood samples and foot print analysis was used to assess functional recovery. At 8-weeks post-nerve injury, sciatic nerves were prepared for light and electron microscopy. In a separate group, Fluro-Gold was injected subcutaneously at the ankle prior to perfusion, and counts and sizes of retrogradely labeled and unlabeled dorsal root ganglion neurons were obtained. There was no difference in the time course of gait recovery in antibody-treated and vehicle-treated animals. The number of myelinated and nonmyelinated axons was the same in the muMab 911-treated crushed nerves and intact nerves, consistent with observed complete recovery. Treatment with muMab 911 did however result in a small decrease in average cell body size on both the intact and injured sides. These results indicate that muMab 911 did not impair functional recovery or nerve regeneration after nerve injury in adult rats. PMID:23531437

Lankford, K L; Arroyo, E J; Liu, C-N; Somps, C J; Zorbas, M A; Shelton, D L; Evans, M G; Hurst, S I; Kocsis, J D

2013-06-25

253

The Study of Diagnostic Efficacy of Nerve Conduction Study Parameters in Cervical Radiculopathy  

PubMed Central

Background: Cervical Radiculopathy (CR) is a neurologic condition characterised by dysfunction of a cervical spinal nerve, the roots of the nerve, or both. Diagnostic criteria for CR are not well defined, and no universally accepted criteria for its diagnosis have been established. Clinical examination, radiological imaging and electrophysiologic evaluation are the different modalities to diagnose CR. The incidence of Cervical Spondylosis and related conditions is increasing in the present scenario and the use of radiologic examination is time consuming and uneconomical for the common Indian setup. Thus, there is a definite need to establish a cost effective, reliable, and accurate means for establishing the diagnosis of cervical radiculopathy. Electrodiagnostic tests are the closest to fulfill these criteria. Aim: To evaluate diagnostic utility of various motor and sensory nerve conduction study parameters in cervical radiculopathy. Setting and Design: It was a cross-sectional study conducted on 100 subjects of age > 40 years. Material and Methods: The consecutive patients clinically diagnosed to have cervical radiculopathy, referred from department of Orthopaedics were prospectively recruited for the motor and sensory nerve conduction study using RMS EMG EP Mark-II. Parameters studied were Compound Muscle Action Potential (CMAP), Distal Motor Latency (DML) and Conduction Velocity (CV) for motor nerves and Sensory Nerve Action Potential (SNAP) and CV for sensory nerves. Statistical Analysis: Study observations and results were analysed to find the Specificity, Sensitivity, Positive Predictive Value and Negative Predictive Value using SPSS 16.0. Results: Among various motor nerve conduction parameters CMAP was found to be more sensitive with high positive predicative value. CV was found to have greater specificity and DML had least negative predictive value. Sensory nerve conduction parameters were found to have less sensitivity but higher specificity as compared to motor parameters. Conclusion: Nerve conduction studies are useful supportive diagnostic tool for suspected cervical radiculopathy as they are found to have reliable sensitivity and specificity. PMID:24551610

Pawar, Sachin; Kashikar, Aditi; Shende, Vinod; Waghmare, Satish

2013-01-01

254

Polyphenylquinoxalines via Aromatic Nucleophilic Displacement  

NASA Technical Reports Server (NTRS)

Polyphenylquinoxalines are produced by an aromatic nucleophilic displacement reaction involving an activated aromatic dihalide with an appropriate quinoxaline monomer. Polyphenylquinoxalines are high temperature thermoplastics used as adhesives, coatings, films and composite matrices. The novelty of this invention is threefold: (1) some of the quinoxaline monomers are new compositions of matter; (2) the phenylquinoxaline polymers which are the end products of the invention are new compositions of matter; and (3) the method of forming the polymers is novel, replacing a more costly prior art process, which is also limited in the kinds of products prepared therefrom.

Hergenrother, Paul M.; Connell, John W.

1988-01-01

255

Tumors of the Cranial Nerves  

Microsoft Academic Search

\\u000a The most frequent tumors of the cranial nerves are referred to as schwannomas (formerly neuromas). They may develop in most\\u000a cranial nerves, except I and II, which do not have Schwann cells, except for very rare cases of ectopic pediatric olfactory\\u000a schwannomas. CNSs account for 8% of intracranial tumors. The incidence is rising since the distribution of MRI became widespread.

Berndt Wowra; Jörg-Christian Tonn

256

Nature of the Retrograde Signal from Injured Nerves that Induces Interleukin6 mRNA in Neurons  

Microsoft Academic Search

In previous studies, interleukin-6 was shown to be synthesized in approximately one-third of lumbar dorsal root ganglion neu- rons during the first week after nerve transection. In present studies, interleukin-6 mRNA was found to be induced also in axotomized facial motor neurons and sympathetic neurons. The nature of the signal that induces interleukin-6 mRNA in neurons after nerve injury was

Patricia G. Murphy; Lindsay S. Borthwick; Robert S. Johnston; George Kuchel; Peter M. Richardson

1999-01-01

257

Displacement Based Multilevel Structural Optimization  

NASA Technical Reports Server (NTRS)

In the complex environment of true multidisciplinary design optimization (MDO), efficiency is one of the most desirable attributes of any approach. In the present research, a new and highly efficient methodology for the MDO subset of structural optimization is proposed and detailed, i.e., for the weight minimization of a given structure under size, strength, and displacement constraints. Specifically, finite element based multilevel optimization of structures is performed. In the system level optimization, the design variables are the coefficients of assumed polynomially based global displacement functions, and the load unbalance resulting from the solution of the global stiffness equations is minimized. In the subsystems level optimizations, the weight of each element is minimized under the action of stress constraints, with the cross sectional dimensions as design variables. The approach is expected to prove very efficient since the design task is broken down into a large number of small and efficient subtasks, each with a small number of variables, which are amenable to parallel computing.

Sobieszezanski-Sobieski, J.; Striz, A. G.

1996-01-01

258

Interferometric fiber optic displacement sensor  

DOEpatents

A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 23 figs.

Farah, J.

1999-04-06

259

Interferometric fiber optic displacement sensor  

DOEpatents

A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 29 figs.

Farah, J.

1995-05-30

260

Amyloplast Distribution Directs a Root Gravitropic Reaction  

NASA Astrophysics Data System (ADS)

Immobile higher plants are oriented in the gravitational field due to gravitropim that is a physiological growth reaction and consists of three phases: reception of a gravitational signal by statocytes, its transduction to the elongation zone, and finally the organ bending. As it is known, roots are characterized with positive gravitropism, i. e. they grow in the direction of a gravitational vector, stems - with negative gravitropism, i. e. they grow in the direction opposite to a gravitational vector. According to the Nemec’s and Haberlandt’s starch-statolith hypothesis, amyloplasts in diameter of 1.5 - 3 ? in average, which appear to act as gravity sensors and fulfill a statolythic function in the specialized graviperceptive cells - statocytes, sediment in the direction of a gravitational vector in the distal part of a cell, while a nucleus is in the proximal one. There are reasonable data that confirm the amyloplasts-statoliths participation in gravity perception: 1) correlation between the statoliths localization and the site of gravity sensing, 2) significant redistribution (sedimentation) of amyloplasts in statocytes under gravistimulation in comparison with other cell organelles, 3) root decreased ability to react on gravity under starch removal from amyloplasts, 4) starchless Arabidopsis thaliana mutants are agravitropic, 5) amyloplasts-statoliths do not sediment in the absence of the gravitational vector and are in different parts or more concentrated in the center of statocytes. Plant tropisms have been intensively studied for many decades and continue to be investigated. Nevertheless, the mechanisms by which plants do so is still not clearly explained and many questions on gravisensing and graviresponse remain unanswered. Even accepted hypotheses are now being questioned and recent data are critically evaluated. Although the available data show the Ca2+ and cytoskeleton participation in graviperception and signal transduction, the clear evidence with regard to the participation of calcium ions and cytoskeletal elements in these processes is therefore substantial but still circumstantial and requires new experimental data. Using a new model - weak combined magnetic fields (CMFs), which elicit a variety of responses in plants, growth rate and fresh weight, seed germination, Ca2+ concentration, membrane permeability, with a frequency resonance to cyclotron frequency of calcium ions, we firstly showed that a root positive gravitropic reaction changes on a negative one. In this case, the paradoxical displacement of amylopasts-statoliths to the upper longitudinal cell wall of statocytes occurred in the direction opposite to a gravitational vector. Displacement of amyloplasts, which contain the abundance of free Ca2+ in the stroma, was accompanied with Ca2+ redistribution in the same direction in the cytosol and increasing around amyloplasts in comparison with the state magnetic field. In the elongation zone, calcium ions accumulated in the upper site of a gravistimulated root unlike a positive gravitropic reaction, and a root is bending in the same direction in which amyloplasts are displacing. It seems that a root gravitropic reaction, if it began, occurs by an usual physiological way resulting in root bending with an opposite sign. It is of a special interest that a root is bending to the same direction with displacing of amyloplasts: in positive gravitropism - downwards, in negative gravitropism - upwards. Peculiarities of calcium ion redistribution in statocytes under gravistimulation in such combined magnetic field are a new additional evidence of a Ca2+ ion significant role in gravitropism. Thus, our data support the starch-statolith hypothesis but also pose the question as to which forces displace amyloplasts against the gravity vector? We hope that these data will stimulate new research to better understand the mechanisms of plant graviperception and graviresponse. Gravistimulation of a root in the CMF with the frequency resonance to the cyclotron frequency of Ca2+ ions is an effective model for future

Kordyum, Elizabeth

261

Pericycle Cell Proliferation and Lateral Root Initiation in Arabidopsis1  

PubMed Central

In contrast with other cells generated by the root apical meristem in Arabidopsis, pericycle cells adjacent to the protoxylem poles of the vascular cylinder continue to cycle without interruption during passage through the elongation and differentiation zones. However, only some of the dividing pericycle cells are committed to the asymmetric, formative divisions that give rise to lateral root primordia (LRPs). This was demonstrated by direct observation and mapping of mitotic figures, cell-length measurements, and the histochemical analysis of a cyclin-GUS fusion protein in pericycle cells. The estimated duration of a pericycle cell cycle in the root apical meristem was similar to the interval between cell displacement from the meristem and the initiation of LRP formation. Developmentally controlled LRP initiation occurs early, 3 to 8 mm from the root tip. Thus the first growth control point in lateral root formation is defined by the initiation of primordia in stochastic patterns by cells passing through the elongation and young differentiation zones, up to where lateral roots begin to emerge from the primary root. Therefore, the first growth control point is not restricted to a narrow developmental window. We propose that late LRP initiation is developmentally unrelated to the root apical meristem and is operated by a second growth control point that can be activated by environmental cues. The observation that pericycle cells divide and lateral root primordia form without intervening mitotic quiescence suggests that lateral organ formation in roots and shoots might not be as fundamentally different as previously thought. PMID:11115882

Dubrovsky, Joseph G.; Doerner, Peter W.; Colon-Carmona, Adan; Rost, Thomas L.

2000-01-01

262

Pericycle cell proliferation and lateral root initiation in Arabidopsis.  

PubMed

In contrast with other cells generated by the root apical meristem in Arabidopsis, pericycle cells adjacent to the protoxylem poles of the vascular cylinder continue to cycle without interruption during passage through the elongation and differentiation zones. However, only some of the dividing pericycle cells are committed to the asymmetric, formative divisions that give rise to lateral root primordia (LRPs). This was demonstrated by direct observation and mapping of mitotic figures, cell-length measurements, and the histochemical analysis of a cyclin-GUS fusion protein in pericycle cells. The estimated duration of a pericycle cell cycle in the root apical meristem was similar to the interval between cell displacement from the meristem and the initiation of LRP formation. Developmentally controlled LRP initiation occurs early, 3 to 8 mm from the root tip. Thus the first growth control point in lateral root formation is defined by the initiation of primordia in stochastic patterns by cells passing through the elongation and young differentiation zones, up to where lateral roots begin to emerge from the primary root. Therefore, the first growth control point is not restricted to a narrow developmental window. We propose that late LRP initiation is developmentally unrelated to the root apical meristem and is operated by a second growth control point that can be activated by environmental cues. The observation that pericycle cells divide and lateral root primordia form without intervening mitotic quiescence suggests that lateral organ formation in roots and shoots might not be as fundamentally different as previously thought. PMID:11115882

Dubrovsky, J G; Doerner, P W; Colón-Carmona, A; Rost, T L

2000-12-01

263

A Theoretical Model to Predict Both Horizontal Displacement and Vertical Displacement for Electromagnetic Induction-Based Deep Displacement Sensors  

PubMed Central

Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors’ mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors’ monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency. PMID:22368467

Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

2012-01-01

264

Discrete square root smoothing.  

NASA Technical Reports Server (NTRS)

The basic techniques applied in the square root least squares and square root filtering solutions are applied to the smoothing problem. Both conventional and square root solutions are obtained by computing the filtered solutions, then modifying the results to include the effect of all measurements. A comparison of computation requirements indicates that the square root information smoother (SRIS) is more efficient than conventional solutions in a large class of fixed interval smoothing problems.

Kaminski, P. G.; Bryson, A. E., Jr.

1972-01-01

265

Gravitropic bending of cress roots without contact between amyloplasts and complexes of endoplasmic reticulum  

Microsoft Academic Search

The polar arrangement of cell organelles in Lepidium root statocytes is persistently converted to a physical stratification during lateral centrifugation (the centrifugal force acts perpendicular to the root long axis) or by apically directed centrifugation combined with cytochalasin-treatment. Lateral centrifugation (10 min, 60 min at 10\\\\g or 50\\\\g) causes displacement of amylplasts to the centrifugal anticlinal cell wall and shifting

Marina Wendt; Ling-Long Kuo-Huang; Andreas Sievers

1987-01-01

266

The spinal cord ventral root: an afferent pathway of the hind-limb pressor reflex in cats.  

PubMed Central

1. In anaesthetized cats the sciatic nerve was cut and the central end was stimulated at a high frequency and voltage. This caused an increase in arterial blood pressure and a rise in heart rate. The pressure response was diminished by dorsal root section but not completely eliminated until ventral root section (L4-S3). The tachycardia response was abolished by dorsal root section alone. 2. In other cats capsaicin was injected intra-arterially into the hind limb, causing elevations in both blood pressure and heart rate. Similar to the sciatic nerve stimulation experiments, the pressor response was principally reduced by dorsal root section but was further significantly decreased by ventral root section (L1-S3). The rise in heart rate was prevented by dorsal root section alone. 3. It is concluded that, in cats, the afferent pathway of the pressor response to sciatic nerve stimulation and to hind-limb capsaicin injection are conducted principally in the dorsal roots but also to a small extent in the ventral roots of the spinal cord. Although the tachycardia response appears to be conducted only through the dorsal roots, it is possible that at lower resting heart rates and by stimulation of a large population of the unmyelinated skeletal muscle afferents, the ventral root is a functional pathway. PMID:7411444

Longhurst, J C; Mitchell, J H; Moore, M B

1980-01-01

267

WHY ROOTING FAILS.  

SciTech Connect

I explore the origins of the unphysical predictions from rooted staggered fermion algorithms. Before rooting, the exact chiral symmetry of staggered fermions is a flavored symmetry among the four 'tastes.' The rooting procedure averages over tastes of different chiralities. This averaging forbids the appearance of the correct 't Hooft vertex for the target theory.

CREUTZ,M.

2007-07-30

268

Displaceable Gear Torque Controlled Driver  

NASA Technical Reports Server (NTRS)

Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

Cook, Joseph S., Jr. (Inventor)

1997-01-01

269

An ion displacement membrame model.  

PubMed

The usual assumption in treating the diffusion of ions in an electric field has been that the movement of each ion is independent of the movement of the others. The resulting equation for diffusion by a succession of spontaneous jumps has been well stated by Parlin and Eyring. This paper will consider one simple case in which a different assumption is reasonable. Diffusion of monovalent positive ions is considered as a series of jumps from one fixed negative site to another. The sites are assumed to be full (electrical neutrality). Interaction occurs by the displacement of one ion by another. An ion leaves a site if and only if another ion, not necessarily of the same species, attempts to occupy the same site. Flux ratios and net fluxes are given as functions of the electrical potential, concentration ratios, and number of sites encountered in crossing the membrane. Quantitative comparisons with observations of Hodgkin and Keynes are presented. PMID:6048876

Hladky, S B; Harris, J D

1967-09-01

270

Polybenzimidazoles Via Aromatic Nucleophilic Displacement  

NASA Technical Reports Server (NTRS)

Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenylbenzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl)benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl)benzimidazoles are synthesized by reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

Connell, John W. (Inventor); Hergerrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

1997-01-01

271

Polyimidazoles via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

Polyimidazoles (Pl) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl)imidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as N,N-dimethylacetamide, sulfolane, N-methylpyrroldinone, dimethylsulfoxide, or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperature under nitrogen. The di(hydroxyphenyl)imidazole monomers are prepared by reacting an aromatic aldehyde with a dimethoxybenzil or by reacting an aromatic dialdehyde with a methoxybenzil in the presence of ammonium acetate. The di(methoxyphenyl)imidazole is subsequently treated with aqueous hydrobromic acid to give the di(hydroxyphenyl)imidazole monomer. This synthetic route has provided high molecular weight Pl of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides and dinitro compounds.

Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor)

1991-01-01

272

Polybenzimidazoles via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl) benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl) benzimidazoles are synthesizedby reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

Connell, John W. (inventor); Hergenrother, Paul M. (inventor); Smith, Joseph G., Jr. (inventor)

1995-01-01

273

To compete or not to compete: an experimental study of interactions between plant species with contrasting root behaviour  

Microsoft Academic Search

Game-theoretic models predict that plants with root systems that avoid belowground competition will be displaced by plants\\u000a that overproduce roots in substrate shared with competitors. Despite this, both types of root response to neighbours have\\u000a been documented. We used two co-occurring clonal species (Glechoma hederacea and Fragaria vesca) with contrasting root responses to neighbours (avoidance of competition and contesting of

Marina Semchenko; Kristjan Zobel; Michael J. Hutchings

2010-01-01

274

Cardiac autonomic nerve distribution and arrhythmia?  

PubMed Central

OBJECTIVE: To analyze the distribution characteristics of cardiac autonomic nerves and to explore the correlation between cardiac autonomic nerve distribution and arrhythmia. DATA RETRIEVAL: A computer-based retrieval was performed for papers examining the distribution of cardiac autonomic nerves, using heart, autonomic nerve, sympathetic nerve, vagus nerve, nerve distribution, rhythm and atrial fibrillation as the key words. SELECTION CRITERIA: A total of 165 studies examining the distribution of cardiac autonomic nerve were screened, and 46 of them were eventually included. MAIN OUTCOME MEASURES: The distribution and characteristics of cardiac autonomic nerves were observed, and immunohistochemical staining was applied to determine the levels of tyrosine hydroxylase and acetylcholine transferase (main markers of cardiac autonomic nerve distribution). In addition, the correlation between cardiac autonomic nerve distribution and cardiac arrhythmia was investigated. RESULTS: Cardiac autonomic nerves were reported to exhibit a disordered distribution in different sites, mainly at the surface of the cardiac atrium and pulmonary vein, forming a ganglia plexus. The distribution of the pulmonary vein autonomic nerve was prominent at the proximal end rather than the distal end, at the upper left rather than the lower right, at the epicardial membrane rather than the endocardial membrane, at the left atrium rather than the right atrium, and at the posterior wall rather than the anterior wall. The main markers used for cardiac autonomic nerves were tyrosine hydroxylase and acetylcholine transferase. Protein gene product 9.5 was used to label the immunoreactive nerve distribution, and the distribution density of autonomic nerves was determined using a computer-aided morphometric analysis system. CONCLUSION: The uneven distribution of the cardiac autonomic nerves is the leading cause of the occurrence of arrhythmia, and the cardiac autonomic nerves play an important role in the occurrence, maintenance, and symptoms of arrhythmia.

Liu, Quan; Chen, Dongmei; Wang, Yonggang; Zhao, Xin; Zheng, Yang

2012-01-01

275

Fiber optic multimode displacement sensor  

SciTech Connect

An underwater Optical Motion Sensor (OMS) based on a design first presented by W. B. Spillman, {ital Schlieren} {ital multimode} {ital fiber}-{ital optic} {ital hydrophone}, Applied Physics Letters 37(2), 15 July 1980, p. 145{endash}146 is described. The displacement sensor uses the same acoustooptical intensity modulation mechanism as Spillman, however the sensing mechanism is isolated from the ambient fluid environment by a small cylindrical aluminum enclosure (1{double_prime} OD{times}3/4{double_prime}). The enclosure contains an inertial mass and the fiber collimators. The inertial mass is suspended in the center of the enclosure by three small wires rigidly mounted to the walls. The mass and wires act as a cantilever beam system with a mechanical resonance near 100 Hz. The transduction mechanism consists of two opposed optical gratings aligned and positioned between the fiber collimators. One grating is mounted on the inertial mass while the other is mounted on the lower end cap of the enclosure. Relative motion between the gratings causes a modulation of the light transmitted through the gratings. The modulated beam is focused onto a photodetector and converted to electric current. The frequency response is flat from 200 Hz{endash}9 kHz with a minimum detectable displacement of 0.002 A and the dynamic range is 136 dB. The small size and light weight give the sensor an effective density of 1.08 g/cm{sup 3} making it almost neutrally buoyant in water. This in conjunction with the performance characteristics make this sensor suitable for use in acoustical sensing applications. {copyright} {ital 1996 American Institute of Physics.}

Fisher, K.A.; Jarzynski, J. [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States)

1996-04-01

276

The Population Genetics of Sperm Displacement  

PubMed Central

This article reports the results of some sperm displacement experiments, as well as the results of a theoretical study of selection arising from genetic differences in displacing ability. The experimental work involved the use of three genetic marker stocks in double and triple matings. The speed of displacement following the matings was determined by scoring the progeny of each female daily. There were clear differences between strains in their displacing ability. It is shown how new information concerning the displacement process results when three markers are used; however, no new light is shed by these experiments on the mechanism of displacement. The theoretical study of selection resulting from displacement uses a one-locus, two-allele model in which three diploid male genotypes confer different displacing abilities. The results indicate stable equilibria if (1) there is heterosis, and (2) there are certain nontransitive relationships in displacing ability among the different kinds of double matings. Some evolutionary consequences are discussed in which sperm displacement is regarded as a form of sexual selection. PMID:838274

Prout, Timothy; Bundgaard, J?rgen

1977-01-01

277

Facial-hypoglossal nerve anastomosis using laser nerve welding.  

PubMed

The aim of this study is to compare laser nerve welding to microsurgical suturing of hypoglossal-facial nerve anastomosis (HFA), and a result of immediate to delayed repair, and to evaluate the effect of laser nerve welding on HFA for reanimation of facial palsy. The first group of five rats underwent immediate HFA by microsurgical suturing and the second group of five rats by CO2 laser welding. The third group of five rats underwent delayed HFA by microsurgical suturing, and the fourth group of five rats by laser nerve welding. The fifth group of five rats served as controls, with intact hypoglossal and facial nerve. In all rats of the four different treatment groups, cholera toxin B subunit (CTb) was injected in the epineurium distal to the anastomosis site on the postoperative 6th week and in the normal hypoglossal nerve in the five rats of the control group. Neurons labeled CTb of hypoglossal nuclei were positive immunohistochemically, and the numbers were counted. In the immediate HFA groups, CTb-positive neurons were 751 +/- 247 in the laser welding group (n = 5) and 888 +/- 60 in the microsurgical suturing group (n = 5). There was no significant difference (P = 0.117). In the delayed HFA groups, CTb-positive neurons were 749 +/- 54 in the laser welding group (n = 5) and 590 +/- 169 in the microsurgical suturing group (n = 5). The difference was not significant (P = 0.116). There was no significant difference between immediate and delayed anastomosis in the laser welding group (P = 0.600), but there was significance between immediate and delayed anastomosis in the microsurgical suturing group (P = 0.009). Injected CTb in intact hypoglossal neurons (n = 5) were labeled 1,003 +/- 52. No dehiscence in the laser welding site of nerve anastomosis was seen at the time of re-exploration for injection of CTb in all 10 rats. This study shows that the regeneration of anastomosed hypoglossal-facial nerve was affected similarly by laser welding and microsurgical suturing, and more effective, especially in delayed repair. PMID:16877915

Hwang, Kun; Kim, Sun Goo; Kim, Dae Joong

2006-07-01

278

Topography and time course of changes in spinal neuropeptide Y immunoreactivity after spared nerve injury  

PubMed Central

We used a new computer-assisted method to precisely localize and efficiently quantify increases in NPY immunoreactivity (NPY-ir) along the mediolateral axis of the L4 dorsal horn following transection of either the tibial and common peroneal nerves (thus sparing the sural branch, spared nerve injury, SNI), the tibial nerve, or the common peroneal and sural nerves. Two weeks after SNI, NPY-ir increased within the tibial and peroneal innervation territories; however, NPY-ir in the central-lateral region (innervated by the spared sural nerve) was indistinguishable from that of SHAM. Conversely, transection of the sural and common peroneal nerved induced an increase in NPY-ir in the central-lateral region, while leaving the medial region (innervated by the tibial nerve) unaffected. All nerve injuries increased NPY-ir in dorsal root ganglia (DRG) and nucleus gracilis (NG). By 24 wk, both NPY-ir up-regulation in the dorsal horn and hyper-responsivity to cold and noxious mechanical stimuli had resolved. Conversely, NPY-ir in DRG and NG, and hypersensitivity to non-noxious static mechanical stimuli, did not resolve within 24 wk. Over this time course, the average cross-sectional area of NPY-immunoreactive DRG neurons increased by 150 ?m2. We conclude that the up-regulation of NPY after SNI is restricted to medial zones of the dorsal horn, and therefore cannot act directly upon synapses within the more lateral (sural) zones to control sural nerve hypersensitivity. Instead, we suggest that NPY in the medial dorsal horn tonically inhibits hypersensitivity by interrupting mechanisms of central sensitization and integration of sensory signals at the spinal and supraspinal levels. PMID:19879928

Intondi, A.B.; Zadina, J.E.; Zhang, X.; Taylor, B.K.

2009-01-01

279

Displacement speeds in turbulent premixed flame simulations  

SciTech Connect

The theory of turbulent premixed flames is based on acharacterization of the flame as a discontinuous surface propagatingthrough the fluid. The displacement speed, defined as the local speed ofthe flame front normal to itself, relative to the unburned fluid,provides one characterization of the burning velocity. In this paper, weintroduce a geometric approach to computing displacement speed anddiscuss the efficacy of the displacement speed for characterizing aturbulent flame.

Day, Marcus S.; Shepherd, Ian G.; Bell, J.; Grcar, Joseph F.; Lijewski, Michael J.

2007-07-01

280

Microbial Adhesion in Flow Displacement Systems  

PubMed Central

Flow displacement systems are superior to many other (static) systems for studying microbial adhesion to surfaces because mass transport and prevailing shear conditions can be adequately controlled and notoriously ill-defined slight rinsing steps to remove so-called “loosely adhering organisms” can be avoided. In this review, we present the basic background required to calculate mass transport and shear rates in flow displacement systems, focusing on the parallel plate flow chamber as an example. Critical features in the design of flow displacement systems are discussed, as well as different strategies for data analysis. Finally, selected examples of working with flow displacement systems are given for diverse biomedical applications. PMID:16418527

Busscher, Henk J.; van der Mei, Henny C.

2006-01-01

281

Peripheral nerve disease in pregnancy.  

PubMed

Neuropathies during pregnancy and the postpartum period are common and are usually due to compression around pregnancy and childbirth. The most common peripheral neuropathies are Bell's palsy, carpal tunnel syndrome (CTS), and lower extremity neuropathies. Although most neuropathies are usually reversible, associated disabilities or morbidities can limit functioning and require therapy. Nerve conduction study tests and imaging should only be considered if symptoms are unusual or prolonged. Some neuropathies may be associated with preeclampsia or an inherent underlying neuropathy that increases the risk of nerve injury. All neuropathies in pregnancy should be followed as some may be persistent and require follow-up. PMID:23563878

Klein, Autumn

2013-06-01

282

Nerve lesioning with direct current  

NASA Astrophysics Data System (ADS)

Spastic hypertonus (muscle over-activity due to exaggerated stretch reflexes) often develops in people with stroke, cerebral palsy, multiple sclerosis and spinal cord injury. Lesioning of nerves, e.g. with phenol or botulinum toxin is widely performed to reduce spastic hypertonus. We have explored the use of direct electrical current (DC) to lesion peripheral nerves. In a series of animal experiments, DC reduced muscle force by controlled amounts and the reduction could last several months. We conclude that in some cases controlled DC lesioning may provide an effective alternative to the less controllable molecular treatments available today.

Ravid, E. Natalie; Shi Gan, Liu; Todd, Kathryn; Prochazka, Arthur

2011-02-01

283

Effect of pulsed infrared lasers on neural conduction and axoplasmic transport in sensory nerves  

NASA Astrophysics Data System (ADS)

Over the past ten years there has been an increasing interest in the use of lasers for neurosurgical and neurological procedures. Novel recent applications range from neurosurgical procedures such as dorsal root entry zone lesions made with argon and carbon dioxide microsurgical lasers to pain relief by low power laser irradiation of the appropriate painful nerve or affected region1 '2 However, despite the widespread clinical applications of laser light, very little is known about the photobiological interactions between laser light and nervous tissue. The present studies were designed to evaluate the effects of pulsed Nd:YAG laser light on neural impulse conduction and axoplasmic transport in sensory nerves in rats and cats. Our data indicate that Q-switched Nd:YAG laser irradiation can induce a preferential impairment of (1) the synaptic effects of small afferent fibers on dorsal horn cells in the spinal cord and of (2) small slow conducting sensory nerve fibers in dorsal roots and peripheral nerves. These results imply that laser light might have selective effects on impulse conduction in slow conducting sensory nerve fibers. In agreement with our elecirophysiological observations recent histological data from our laboratory show, that axonal transport of the enzyme horseradish peroxidase is selectively impaired in small sensory nerve fibers. In summary these data indicate, that Q-switched Nd:YAG laser irradiation can selectively impair neural conduction and axoplasmic transport in small sensory nerve fibers as compared to fast conducting fibers. A selective influence of laser irradiation on slow conducting fibers could have important clinical applications, especially for the treatment of chronic pain.

Wesselmann, Ursula; Rymer, William Z.; Lin, Shien-Fong

1990-06-01

284

Intermuscular lipoma of the gluteus muscles compressing the sciatic nerve: an inverted sciatic hernia.  

PubMed

The authors report the case of a 50-year-old woman with a benign intermuscular lipoma of the gluteus compressing the sciatic nerve in its course through the sciatic notch. This benign soft-tissue tumor extended into the pelvis, displacing the rectum laterally. Resection was necessary to alleviate symptoms and prevent irreversible damage of the nerve. Wide exposure of the piriformis muscle and sciatic nerve via a transgluteal approach allowed safe lesion removal, and thus avoiding a laparotomy to resect the intrapelvic extension of the tumor. This report features a curious case of soft-tissue tumor growth across the sciatic foramen forming an inverted sciatic hernia. The authors' proposed approach was simple and safe and avoided a laparotomy. PMID:22900844

López-Tomassetti Fernández, Eudaldo M; Hernández, Juan Ramón Hernández; Esparragon, Jose Ceballos; García, Angel Turegano; Jorge, Valentin Nuñez

2012-10-01

285

Managing Chemotherapy Side Effects: Nerve Changes  

MedlinePLUS

... services national institutes of health Managing Chemotherapy Side Effects Nerve Changes “My fingers and toes felt numb ... or constipation l Stomach pain Managing Chemotherapy Side Effects: Nerve Changes Try these tips from others: “Prevent ...

286

Nerve Agents ATSDR ? General Information 1  

E-print Network

Nerve Agents ATSDR ? General Information 1 Nerve Agents Tabun (GA) CAS 77-81-6; Sarin (GB) CAS 107 are heavier thanair. Odor does not provide adequate warning of detection. The estimated LCt50 (the product

Baloh, Bob

287

Infraspinatus muscle atrophy from suprascapular nerve compression.  

PubMed

Muscle weakness without pain may signal a nerve compression injury. Because these injuries should be identified and treated early to prevent permanent muscle weakness and atrophy, providers should consider suprascapular nerve compression in patients with shoulder muscle weakness. PMID:24463748

Cordova, Christopher B; Owens, Brett D

2014-02-01

288

Continuous Displacement Formulation of Alloys  

NASA Astrophysics Data System (ADS)

The conventional permutational statistics of cooperative phenomena is extended to include displacement of atoms from their reference lattice points. The formulation is done in the cluster variation method (CVM) framework, by changing summations in energy and entropy to integrals. It is demonstrated for the pair approximation of CVM on phase-separating fcc binary alloys. The treatment can take into account local lattice distortion due to atomic size difference, the elastic effects, and the pressure effects. To compare stability of states under pressure, the grand potential ?( T, V, { ? i}) is extended to Z( T, p, { ? i}) by a Legendre transform. Although the new function Z( T, p, { ? i}) vanishes in equilibrium, and is called the ZERO-potential in the paper, it remains nonzero and is used to determine the coexisting phases when the chemical potentials are modified. Numerical calculations are done using the natural iteration technique on model inter-atomic potentials of the Lennard-Jones type. The numerical results of using ?( T, V, { ? i}) and Z( T, p, { ? i}) potentials for phase-separating diagrams, for composition and pressure dependence of the lattice constant, and for the bulk modulus are reported and discussed.

Kikuchi, Ryoichi

1999-06-01

289

Polybenzoxazole via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

Polybenzoxazoles (PBO) are heterocyclic macromolecules which were first synthesized in a two-step process by the initial formation of aromatic diacid chlorides with bis(o-aminophenol)s through solution condensation of aromatic diacid chlorides with bis(o-aminophenol)s followed by thermal cyclodehydration. Since then several methods were utilized in their synthesis. The most common synthetic method for PBO involves a polycondensation of bis(o-aminophenol)s with aromatic diacid diphenyl esters. Another preparative route involves the solution polycondensation of the hydrochloride salts of bis(o-amino phenol)s with aromatic diacids in polyphosphoric acid. Another synthetic method involves the initial formation of poly(o-hydroxy amide)s from silylated bis(o-aminophenol)s with aromatic diacid chlorides followed by thermal cyclodehydration to PBO. A recent preparative route involves the reaction of aromatic bisphenols with bis(fluorophenyl) benzoxazoles by the displacement reaction to form PBO. The novelty of the present invention is that high molecular weight PBO of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

Hergenrother, Paul M. (inventor); Connell, John W. (inventor); Smith, Joseph G., Jr. (inventor)

1993-01-01

290

Continuous Vagal Nerve Stimulation for Recurrent Laryngeal Nerve Protection in Thyroid Surgery  

Microsoft Academic Search

Introduction: Newly developed vagal stimulation probes permit continuous intraoperative neuromonitoring of the recurrent laryngeal nerve during thyroid resection. Complete signal loss indicates damage of the nerve. There is no other criterion so far to warn before imminent nerve function impairment. Methods: In 100 patients, thyroid resection (188 nerves at risk, 52 thyroidectomies, 21 Dunhill resections, 12 hemithyroidectomies, 5 two-sided subtotal

J. Jonas

2010-01-01

291

Video-Gait Analysis of Functional Recovery of Nerve Repaired with Chitosan Nerve Guides  

E-print Network

guides is commonly evaluated through histomorphometry and walking track analysis. We conducted a unique of nerve guide tubes is considered an alternative method to achieve nerve regeneration of transected nerves method of autografts.5­9 Currently a vast amount of research is being pursued to engineer the ideal nerve

VandeVord, Pamela

292

Supraclavicular nerve entrapment and clavicular fracture.  

PubMed

Because the supraclavicular nerve lies in close proximity to the clavicle, it is particularly vulnerable to injury in cases of clavicle fracture and in the surgical treatment of these fractures. The development of painful neuromas after iatrogenic transsection and symptomatic nerve entrapment in fracture callus after healing have previously been described. Reported here is a case of acute supraclavicular nerve entrapment and tension after fracture of the clavicle with significant pain relief after fracture fixation and nerve decompression. PMID:22430514

O?Neill, Kevin; Stutz, Christopher; Duvernay, Matthew; Schoenecker, Jonathan

2012-06-01

293

Proximal Sciatic Nerve Intraneural Ganglion Cyst  

PubMed Central

Intraneural ganglion cysts are nonneoplastic, mucinous cysts within the epineurium of peripheral nerves which usually involve the peroneal nerve at the knee. A 37-year-old female presented with progressive left buttock and posterior thigh pain. Magnetic resonance imaging revealed a sciatic nerve mass at the sacral notch which was subsequently revealed to be an intraneural ganglion cyst. An intraneural ganglion cyst confined to the proximal sciatic nerve has only been reported once prior to 2009. PMID:20069041

Swartz, Karin R.; Wilson, Dianne; Boland, Michael; Fee, Dominic B.

2009-01-01

294

A cadaver study to determine the minimum volume of methylene blue or black naphthol required to completely color the nerves relevant for anesthesia during breast surgery.  

PubMed

Regional anesthesia for breast surgery may require a large amount of local anesthetic solution to provide an adequate blockade of all relevant structures. The purpose of this study was to determine the minimal volume of fluid required to anesthetize all nerves to adequately provide anesthesia for breast surgery. This is an open randomized study. Cadavers were embalmed using Thiel's technique and were injected with different volumes of 0.2% methylene blue or 0.2% black naphthol for a superficial cervical plexus block (2, 5, 10, or 15 mL), an interscalene block (5, 10, 15, or 20 mL), paravertebral blocks from C(8) to T(6), and intercostal nerve blocks at 8 cm from the midline (2 or 3 mL) under ultrasound-guided or assisted techniques. The following minimal volumes of fluid were required for complete coloration of the nerves: 2 mL for the supraclavicular nerves; 20 mL for the nerve roots from C(5) to C(7), inclusive, if intraneural injection was avoided; 3 mL per root for the nerve roots from C(8) to T(6), inclusive, for a paravertebral block; and 2 mL per nerve for intercostal nerve blocks at T(4) and lower. With 20 mL of solution at the interscalene level, the roots of C(3) and C(4) were also colored; therefore, a separate injection for the supraclavicular nerves was unnecessary. We conclude that regional anesthesia for complex breast surgery can be achieved with a volume of local anesthetic as low as 41 mL. PMID:21322042

Guay, Joanne; Grabs, Detlev

2011-03-01

295

Effects of Fault Displacement on Emplacement Drifts  

SciTech Connect

The purpose of this analysis is to evaluate potential effects of fault displacement on emplacement drifts, including drip shields and waste packages emplaced in emplacement drifts. The output from this analysis not only provides data for the evaluation of long-term drift stability but also supports the Engineered Barrier System (EBS) process model report (PMR) and Disruptive Events Report currently under development. The primary scope of this analysis includes (1) examining fault displacement effects in terms of induced stresses and displacements in the rock mass surrounding an emplacement drift and (2 ) predicting fault displacement effects on the drip shield and waste package. The magnitude of the fault displacement analyzed in this analysis bounds the mean fault displacement corresponding to an annual frequency of exceedance of 10{sup -5} adopted for the preclosure period of the repository and also supports the postclosure performance assessment. This analysis is performed following the development plan prepared for analyzing effects of fault displacement on emplacement drifts (CRWMS M&O 2000). The analysis will begin with the identification and preparation of requirements, criteria, and inputs. A literature survey on accommodating fault displacements encountered in underground structures such as buried oil and gas pipelines will be conducted. For a given fault displacement, the least favorable scenario in term of the spatial relation of a fault to an emplacement drift is chosen, and the analysis is then performed analytically. Based on the analysis results, conclusions are made regarding the effects and consequences of fault displacement on emplacement drifts. Specifically, the analysis will discuss loads which can be induced by fault displacement on emplacement drifts, drip shield and/or waste packages during the time period of postclosure.

F. Duan

2000-04-25

296

Alternative sites for intraoperative monitoring of cranial nerves X and XII during intracranial surgeries.  

PubMed

During intracranial surgeries, cranial nerve (CN) X is most commonly monitored with electromyographic endotracheal tubes. Electrodes on these endotracheal tubes may be displaced from the vocal folds during positioning, and there is a learning curve for their correct placement. Cranial nerve XII is most commonly monitored with electrodes in the dorsum of the tongue, which are also prone to displacement because of their proximity to the endotracheal tube. A retrospective review was conducted of a consecutive series of 83 skull base surgeries using alternative sites for monitoring CN X and XII. On-going (spontaneous) and evoked electromyography (EMG) were obtained from the cricothyroid muscle for CN X and submental genioglossus for CN XII. Stimulation of CN X or XII evoked specific compound motor action potentials from these muscles, and well-defined on-going EMG was observed during tumor resection in the vicinity of CN X and XII. Volume-conducted responses from the adjacent platysma muscle during CN VII stimulation were identified by concomitant responses from the orbicularis oris and oculi. In conclusion, during skull base surgeries, CN X may be monitored with electrodes in the cricothyroid muscle and CN XII with electrodes in the submental genioglossus. These alternative sites are less prone to displacement of electrodes compared with the more commonly used EMG endotracheal tube and electrodes in the dorsum of the tongue. The cricothyroid muscle should not be used when the recurrent laryngeal nerve is at risk. PMID:23733092

Holdefer, Robert N; Kinney, Gregory A; Robinson, Larry R; Slimp, Jefferson C

2013-06-01

297

Bifid median nerve: Report of two cases  

Microsoft Academic Search

Summary The median nerve divides into its terminal branches at or proximal to the distal edge of the flexor retinaculum. An anatomy of the median nerve within the carpal tunnel is reported in two separate cases. Emphasis has been given to the value of direct vision when incising the flexor retinaculum in order to avoid injure of the median nerve.

M. Artico; L. Cervoni; G. Stevanato; V. D. Andrea; F. Nucci

1995-01-01

298

Assesing tree-root & soil interaction using pull-out test apparatus  

NASA Astrophysics Data System (ADS)

Knowing in situ root strength provides a better understanding of the responses of tree root systems against external loads. Root pullout devices are used to record these strengths and can be expressed in two ways: pullout force, which is a direct output from the load cell (measured in pounds) or pullout stress, which is the pullout force divided by root cross section area (measured in pounds per square in.). Pullout tests show not only the possible tensile strength of a tree root, but also the interaction between the tree root and the surrounding geological materials. After discussion with engineers from the University of Nottingham-Trent, the U.S. Army Engineer Research and Development Center (ERDC) constructed a root pullout apparatus with some modifications. These modifications included using a T-System configuration at the base of an aluminum frame instead of a diagonal rod and varying the size of the clamp placed around the tested root. The T-System is placed in front of the root perpendicular to the root path. In the ERDC pullout device, the root was pulled directly without a lever system. A string pot was used to measure displacement when the root was pulled. The device is capable of pulling tree roots with a diameter of up to 2.5 in. and a maximum load of 5000 lbs. Using this device, ERDC conducted field operations in Portland, Oregon; Burlington, Washington; and Albuquerque, New Mexico, on Oregon ash, alder, maple, and cedar trees. In general, pullout tests were conducted approximately 60 deg around the tree selected for the tests. The location of a test depended on the availability of a root near the ground surface. A backhoe was used to remove soil around the tree to locate roots. Before the root was secured in a clamp, root diameter was measured and recorded, and the root was photographed. The tree species, dip angle and dip direction of the root, root location with respect to the tree, tree location, dates, weather, and soil type were also recorded. When the test begins the load cell and displacement transducers immediately started recording the measurements, and the measurements are stored on a laptop computer. The hydraulic pump controls the rate of loading for a relatively slow pulling displacement rate of 0.08 in./sec. Failure occurred when the root breaks or was pulled out of the soil. Maximum forces and root failure location were noted, as well as any additional observations during and after the test. In the ERDC tests, root diameters (root with bark) ranged between 0.7 and 2.33 in., the pullout force was between 86 and 3513 lb, and the pullout stress was between 56 and 2645 psi. ERDC recorded three different types of tree-root failures: pure root tensile failure, bonding between root and soil failure, and a combination of the two. In tensile failure, a root breaks abruptly and the force versus displacement curve usually shows a steep slope, and there is no residual strength. In a bonding failure, the force versus displacement curve shows a gentler slope, and there is residual strength. A combined failure mode may also occur. For pullout tests conducted for the ERDC research, the combined mode failure was the most prevalent failure mechanism.

Wibowo, J.; Corcoran, M. K.; Kala, R.; Leavell, D.

2011-12-01

299

Nerve identification and prevention of intraneural injection in regional anesthesia  

Microsoft Academic Search

This thesis deals with techniques to more reliably identify nervous structures and subsequently prevent intraneural injection in the practice of regional anesthesia. To identify nerves of the brachial plexus and sciatic nerve, both conventional techniques such as nerve stimulation, as well as ultrasound are described. The first chapters deal with nerve identification techniques using nerve stimulation and ultrasound. Nerve stimulation

Nizar Moayeri

2010-01-01

300

SUNCT and optic nerve hypoplasia  

Microsoft Academic Search

SUNCT has been reported in association with abnormalities of the brainstem and pituitary region. We present a patient with\\u000a a history of left optic nerve hypoplasia, mild hypothalamic-pituitary dysfunction, and SUNCT starting in adolescence. SUNCT\\u000a with an early age of onset may be associated with congenital abnormality of the hypothalamic-pituitary axis.

Brett J. Theeler; Kevin R. Joseph

2009-01-01

301

The Optical Stretcher Nerve Regeneration  

E-print Network

to test their relevance and importance for biological function. Our ultimate goal is the transfer of our present after neurological trauma to see whether those pose mechanical barriers to nerve regeneration. We are also investigating the importance of mechanical cues for normal differentiation and axonal pathfinding

Steiner, Ullrich

302

Ultrasound of nerve and muscle  

Microsoft Academic Search

Over the last two decades, ultrasound has developed into a useful technology for the evaluation of diseases of nerve and muscle. Since it is currently not used at by the majority of clinicians involved in diagnosis or care of patients with neuromuscular disorders, this review briefly describes the technical aspects of ultrasound and its physical principles. It relates normal muscle

Francis O Walker; Michael S Cartwright; Ethan R Wiesler; James Caress

2004-01-01

303

Is Maxwell's Displacement Current a Current?  

ERIC Educational Resources Information Center

Discusses in detail the claim that certain well-known physics experiments demonstrate the magnetic field produced by Maxwell's displacement current. Addresses the question of whether the displacement current acts as a source of magnetic field in the same way as a current in a wire would. (Contains 12 references.) (WRM)

French, A. P.

2000-01-01

304

BLOCK DISPLACEMENT METHOD FIELD DEMONSTRATION AND SPECIFICATIONS  

EPA Science Inventory

The Block Displacement technique has been developed as a remedial action method for isolating large tracks of ground contaminated by hazardous waste. The technique places a low permeability barrier around and under a large block of contaminated earth. The Block Displacement proce...

305

Horizontal displacements of rock foundations of dams  

SciTech Connect

This paper uses geodetic survey methods to assess the horizontal displacements of dam foundations for several hydroelectric power plants in the Soviet Union. The effects of filling the reservoirs are outlined and the dependence of the degree of displacement on dam height is analyzed. The results are tabulated.

Karlson, A.A.

1987-08-01

306

A linear stability analysis for miscible displacements  

Microsoft Academic Search

A linear stability analysis has been performed for a miscible displacement in a semi-infinite system of finite thickness and unbounded width. A more general description of dispersion has been adopted than those used by previous workers. It is shown that, when there is a step change in concentration and the mobility ratio is unfavorable, the displacement can be unstable at

Shih-Hsien Chang; John C. Slattery

1986-01-01

307

Optic nerve regeneration with return of vision through an autologous peripheral nerve graft.  

PubMed

The optic fiber termination layer in the contralateral optic tectum was reinnervated and useful vision was recovered in the adult frog, after successful optic nerve regeneration through an autologous peripheral nerve-bridge used to replace the optic nerve and optic chiasma. During their course through the nerve-bridge, the optic fibers were associated with Schwann cells in the usual relationship observed in peripheral nerve. PMID:1511315

Scalia, F; Roca, S

1992-07-10

308

Detection of peripheral nerve pathology  

PubMed Central

Objective: To compare accuracy of ultrasound and MRI for detecting focal peripheral nerve pathology, excluding idiopathic carpal or cubital tunnel syndromes. Methods: We performed a retrospective review of patients referred for neuromuscular ultrasound to identify patients who had ultrasound and MRI of the same limb for suspected brachial plexopathy or mononeuropathies, excluding carpal/cubital tunnel syndromes. Ultrasound and MRI results were compared to diagnoses determined by surgical or, if not performed, clinical/electrodiagnostic evaluation. Results: We identified 53 patients who had both ultrasound and MRI of whom 46 (87%) had nerve pathology diagnosed by surgical (n = 39) or clinical/electrodiagnostic (n = 14) evaluation. Ultrasound detected the diagnosed nerve pathology (true positive) more often than MRI (43/46 vs 31/46, p < 0.001). Nerve pathology was correctly excluded (true negative) with equal frequency by MRI and ultrasound (both 6/7). In 25% (13/53), ultrasound was accurate (true positive or true negative) when MRI was not. These pathologies were typically (10/13) long (>2 cm) and only occasionally (2/13) outside the MRI field of view. MRI missed multifocal pathology identified with ultrasound in 6 of 7 patients, often (5/7) because pathology was outside the MRI field of view. Conclusions: Imaging frequently detects peripheral nerve pathology and contributes to the differential diagnosis in patients with mononeuropathies and brachial plexopathies. Ultrasound is more sensitive than MRI (93% vs 67%), has equivalent specificity (86%), and better identifies multifocal lesions than MRI. In sonographically accessible regions ultrasound is the preferred initial imaging modality for anatomic evaluation of suspected peripheral nervous system lesions. PMID:23553474

Seelig, Michael J.; Baker, Jonathan C.; Mackinnon, Susan E.; Pestronk, Alan

2013-01-01

309

SYNAPTIC INHIBITION IN AN ISOLATED NERVE CELL  

PubMed Central

Following the preceding studies on the mechanisms of excitation in stretch receptor cells of crayfish, this investigation analyzes inhibitory activity in the synapses formed by two neurons. The cell body of the receptor neuron is located in the periphery and sends dendrites into a fine muscle strand. The dendrites receive innervation through an accessory nerve fiber which has now been established to be inhibitory. There exists a direct peripheral inhibitory control mechanism which can modulate the activity of the stretch receptor. The receptor cell which can be studied in isolation was stimulated by stretch deformation of its dendrites or by antidromic excitation and the effect of inhibitory impulses on its activity was analyzed. Recording was done mainly with intracellular leads inserted into the cell body. 1. Stimulation of the relatively slowly conducting inhibitory nerve fiber either decreases the afferent discharge rate or stops impulses altogether in stretched receptor cells. The inhibitory action is confined to the dendrites and acts on the generator mechanism which is set up by stretch deformation. By restricting depolarization of the dendrites above a certain level, inhibition prevents the generator potential from attaining the "firing level" of the cell. 2. The same inhibitory impulse may set up a postsynaptic polarization or a depolarization, depending on the resting potential level of the cell. The membrane potential at which the inhibitory synaptic potential reverses its polarity, the equilibrium level, may vary in different preparations. The inhibitory potentials increase as the resting potential is displaced in any direction from the inhibitory equilibrium. 3. The inhibitory potentials usually rise to a peak in about 2 msec. and decay in about 30 msec. After repetitive inhibitory stimulation a delayed secondary polarization phase has frequently been seen, prolonging the inhibitory action. Repetitive inhibitory excitation may also be followed by a period of facilitation. Some examples of "direct" excitation by the depolarizing action of inhibitory impulses are described. 4. The interaction between antidromic and inhibitory impulses was studied. The results support previous conclusions (a) that during stretch the dendrites provide a persisting "drive" for the more central portions of the receptor cell, and (b) that antidromic all-or-none impulses do not penetrate into the distal portions of stretch-depolarized dendrites. The "after-potentials" of antidromic impulses are modified by inhibition. 5. Evidence is presented that inhibitory synaptic activity increases the conductance of the dendrites. This effect may occur in the absence of inhibitory potential changes. PMID:13252239

Kuffler, Stephen W.; Eyzaguirre, Carlos

1955-01-01

310

Morphological studies of the vestibular nerve  

NASA Technical Reports Server (NTRS)

The anatomy of the intratemporal part of the vestibular nerve in man, and the possible age related degenerative changes in the nerve were studied. The form and structure of the vestibular ganglion was studied with the light microscope. A numerical analysis of the vestibular nerve, and caliber spectra of the myelinated fibers in the vestibular nerve branches were studied in individuals of varying ages. It was found that the peripheral endings of the vestibular nerve form a complicated pattern inside the vestibular sensory epithelia. A detailed description of the sensory cells and their surface organelles is included.

Bergstroem, B.

1973-01-01

311

Leptin-sensitive sensory nerves innervate white fat  

PubMed Central

Leptin, the primary white adipose tissue (WAT) adipokine, is thought to convey lipid reserve information to the brain via the circulation. Because WAT responds to environmental/internal signals in a fat pad-specific (FPS) manner, systemic signals such as leptin would fail to communicate such distinctive information. Saturation of brain leptin transport systems also would fail to convey increased lipid levels beyond that point. WAT possesses sensory innervation exemplified by proven sensory-associated peptides in nerves within the tissue and by viral sensory nerve-specific transneuronal tract tracer, H129 strain of herpes simplex virus 1 labeling of dorsal root ganglia (DRG) pseudounipolar neurons, spinal cord and central sensory circuits. Leptin as a paracrine factor activating WAT sensory innervation could supply the brain with FPS information. Therefore, we tested for and found the presence of the long form of the leptin receptor (Ob-Rb) on DRG pseudounipolar neurons immunohistochemically labeled after injections of Fluorogold, a retrograde tract tracer, into inguinal WAT (IWAT). Intra-IWAT leptin injections (300 ng) significantly elevated IWAT nerve spike rate within 5 min and persisted for at least 30 min. Intra-IWAT leptin injections also induced significant c-Fos immunoreactivity (ir), indicating neural activation across DRG pseudounipolar sensory neurons labeled with Fluorogold IWAT injections. Intraperitoneal leptin injection did not increase c-Fos-ir in DRG or the arcuate nucleus, nor did it increase arcuate signal transducer and activator of transcription 3 phosphorylation-ir. Collectively, these results strongly suggest that endogenous leptin secreted from white adipocytes functions as a paracrine factor to activate spinal sensory nerves innervating the tissue. PMID:23612999

Murphy, Keegan T.; Schwartz, Gary J.; Nguyen, Ngoc Ly T.; Mendez, Jennifer M.; Ryu, Vitaly

2013-01-01

312

Facial nerve demyelination and vascular compression are both needed to induce facial hyperactivity: A study in rats  

Microsoft Academic Search

Summary It is generally assumed that hemifacial spasm (HFS) is caused by vascular compression of the facial nerve at the root exit zone (REZ), but the mechanism for the development of HFS is not known. Evidence has been previously presented that the signs of HFS are caused by hyperactivity of the facial motonucleus that is caused by the irritation to

A. Kuroki; A. R. Møller

1994-01-01

313

Intraplantar injection of nerve growth factor into the rat hind paw: local edema and effects on thermal nociceptive threshold  

Microsoft Academic Search

Nerve growth factor (NGF) is known to produce hyperalgesia as well as to stimulate synthesis of neuropeptides in dorsal root ganglia (DRG). In the present study, we wanted to determine the effects of local NGF administration and assess to which extent mast cell-dependent factors are mediating NGF responses. Rats received 1 daily unilateral intraplantar injection for 3 days. Local edema

Rainer Amann; Rufina Schuligoi; Gernot Herzeg; Josef Donnerer

1996-01-01

314

'Nerves': folk idiom for anxiety and depression?  

PubMed

This study suggests that 'nerves' as presented in a primary care clinic is a lay idiom for emotional distress and documents a relationship between the folk ailment 'nerves' and anxiety and depression. One hundred and forty-nine patients at a Virginia clinic were studied, 47 with 'nerves', and 102 controls. Testing with the General Health Questionnaire (GHQ) and the Beck Depression Inventory (BDI) showed 'nerves' patients to be more anxious and depressed than controls. 'Nerves' patients had a mean GHQ score of 13.0 compared to 5.8 for controls (P less than 0.0001) and a BDI score of 7.6 compared to 2.5 for controls (P less than 0.0001). Testing with the Holmes-Rahe Social Readjustment Rating Scale showed 'nerves' patients to suffer more recent life stresses than controls: 'nerves' patients had a mean score of 187.1 compared to 119.3 for controls (P less than 0.05). 'Nerves' patients had somatic symptoms including gastrointestinal disturbances, headaches and shaking. 'Nerves' is most common among women and housewives, and is often attributed to misfortune and tragedy. The ethnomedical illness 'nerves' encompasses a rich array of cultural meanings reflecting the lifestyle and worldview of its sufferers. Despite its chronic debilitating nature, it is rarely recognized by physicians; it is, however, treated by alternative healers. Clinical implications are discussed and recommendations advanced, among them that physicians work with such healers in the recognition and treatment of 'nerves'. PMID:3206246

Nations, M K; Camino, L A; Walker, F B

1988-01-01

315

Symmetric Lipofibromatous Hamartoma Affecting Digital Nerves  

PubMed Central

Lipofibromatous hamartoma of the nerve is a benign tumor, which affects the major nerves and their branches in the human body. It is often found in the median nerve of the hand and is commonly associated with macrodactyly, but it is rarely found in the digital nerves at the peripheral level. This tumor is often found in young adults and may go through a self-limiting course. However, operation is indicated when the tumor size is large or when the associated nerve compressive symptoms are present. We have experienced a rare case of lipofibromatous hamartoma that symmetrically involved the volar digital nerves of both index fingers on the ulnar side. With the aid of a microscope, we dissected and removed the tumor as much as possible without sacrificing the nerve. No sensory change occurred in both fingers and no sign of recurrence was observed upon follow-up. PMID:15744823

Jung, Sung-No; Yim, Youngmin

2005-01-01

316

Optic Nerve Pathway Gliomas and Optic Nerve Meningiomas  

Microsoft Academic Search

\\u000a Optic pathway gliomas are intrinsic slow-growing brain tumors that are the most common primary neoplasms of the optic pathways.\\u000a Optic pathway gliomas are associated with neurofibromatosis type 1; the incidence of optic nerve glioma in patients with this\\u000a syndrome varies from 8% to 31%. Sporadic optic pathway gliomas present with visual symptoms, the most common of which is decreased\\u000a visual

Sonali Singh; Jade S. Schiffman

317

Morphology and Nanomechanics of Sensory Neurons Growth Cones following Peripheral Nerve Injury  

PubMed Central

A prior peripheral nerve injury in vivo, promotes a rapid elongated mode of sensory neurons neurite regrowth in vitro. This in vitro model of conditioned axotomy allows analysis of the cellular and molecular mechanisms leading to an improved neurite re-growth. Our differential interference contrast microscopy and immunocytochemistry results show that conditioned axotomy, induced by sciatic nerve injury, did not increase somatic size of adult lumbar sensory neurons from mice dorsal root ganglia sensory neurons but promoted the appearance of larger neurites and growth cones. Using atomic force microscopy on live neurons, we investigated whether membrane mechanical properties of growth cones of axotomized neurons were modified following sciatic nerve injury. Our data revealed that neurons having a regenerative growth were characterized by softer growth cones, compared to control neurons. The increase of the growth cone membrane elasticity suggests a modification in the ratio and the inner framework of the main structural proteins. PMID:23418549

Szabo, Vivien; Vegh, Attila-Gergely; Lucas, Olivier; Cloitre, Thierry; Scamps, Frederique; Gergely, Csilla

2013-01-01

318

Myelinated sensory and alpha motor axon regeneration in peripheral nerve neuromas  

NASA Technical Reports Server (NTRS)

Histochemical staining for carbonic anhydrase and cholinesterase (CE) activities was used to analyze sensory and motor axon regeneration, respectively, during neuroma formation in transected and tube-encapsulated peripheral nerves. Median-ulnar and sciatic nerves in the rodent model permitted testing whether a 4 cm greater distance of the motor neuron soma from axotomy site or intrinsic differences between motor and sensory neurons influenced regeneration and neuroma formation 10, 30, and 90 days later. Ventral root radiculotomy confirmed that CE-stained axons were 97% alpha motor axons. Distance significantly delayed axon regeneration. When distance was negligible, sensory axons grew out sooner than motor axons, but motor axons regenerated to a greater quantity. These results indicate regeneration differences between axon subtypes and suggest more extensive branching of motor axons within the neuroma. Thus, both distance from injury site to soma and inherent motor and sensory differences should be considered in peripheral nerve repair strategies.

Macias, M. Y.; Lehman, C. T.; Sanger, J. R.; Riley, D. A.

1998-01-01

319

Changes induced by peripheral nerve injury in the morphology and nanomechanics of sensory neurons  

NASA Astrophysics Data System (ADS)

Peripheral nerve injury in vivo promotes a regenerative growth in vitro characterized by an improved neurite regrowth. Knowledge of the conditioning injury effects on both morphology and mechanical properties of live sensory neurons could be instrumental to understand the cellular and molecular mechanisms leading to this regenerative growth. In the present study, we use differential interference contrast microscopy, fluorescence microscopy and atomic force microscopy (AFM) to show that conditioned axotomy, induced by sciatic nerve injury, does not increase somatic size of sensory neurons from adult mice lumbar dorsal root ganglia but promotes the appearance of longer and larger neurites and growth cones. AFM on live neurons is also employed to investigate changes in morphology and membrane mechanical properties of somas of conditioned neurons following sciatic nerve injury. Mechanical analysis of the soma allows distinguishing neurons having a regenerative growth from control ones, although they show similar shapes and sizes.

Benzina, Ouafa; Szabo, Vivien; Lucas, Olivier; Saab, Marie-belle; Cloitre, Thierry; Scamps, Frédérique; Gergely, Csilla; Martin, Marta

2013-06-01

320

Irrational Square Roots  

ERIC Educational Resources Information Center

If students are presented the standard proof of irrationality of [square root]2, can they generalize it to a proof of the irrationality of "[square root]p", "p" a prime if, instead of considering divisibility by "p", they cling to the notions of even and odd used in the standard proof?

Misiurewicz, Michal

2013-01-01

321

ROOT Statistical Software  

E-print Network

Advanced mathematical and statistical computational methods are required by the LHC experiments for analyzing their data. Some of these methods are provided by the ROOT project, a C++ Object Oriented framework for large scale data handling applications. We review the current mathematical and statistical classes present in ROOT, emphasizing the recent developments.

Moneta, Lorenzo; Brun, R; Kreshuk, Anna

2008-01-01

322

Development and Evolution of Character Displacement  

PubMed Central

Character displacement occurs when competition for either resources or successful reproduction imposes divergent selection on interacting species, causing divergence in traits associated with resource use or reproduction. Here, we describe how character displacement can be mediated either by genetically canalized changes (i.e., changes that reflect allelic or genotype frequency changes) or by phenotypic plasticity. We also discuss how these two mechanisms influence the tempo of character displacement. Specifically, we suggest that, under some conditions, character displacement mediated by phenotypic plasticity might occur more rapidly than that mediated by genetically canalized changes. Finally, we describe how these two mechanisms may act together and determine character displacement’s mode, such that it proceeds through an initial phase in which trait divergence is environmentally induced to a later phase in which divergence becomes genetically canalized. This plasticity-first hypothesis predicts that character displacement should be generally mediated by ancestral plasticity and that it will arise similarly in multiple, independently evolving populations. We conclude by highlighting future directions for research that would test these predictions. PMID:22257002

Pfennig, David W.; Pfennig, Karin S.

2012-01-01

323

TPCP: Armillaria Root Rot ARMILLARIA ROOT ROT  

E-print Network

. Armillaria root rot usually becomes apparent when indigenous forests are cleared for afforestation to the fact that indigenous forests are uncommon and few plantations have been established on stands where unsuccessful. It has been found that infection centres apparently disappear after a number of pine rotations

324

The sihler staining study of the infraorbital nerve and its clinical complication.  

PubMed

The infraorbital nerve (ION) is a cardinal cutaneous nerve that provides general sensation to the mid face. Its twigs are vulnerable to iatrogenic damage during medical and dental manipulations. The aims of this study were to elucidate the distribution pattern of the ION and thus help to prevent nerve damage during medical procedures and to enable accurate prognostic evaluation where complications do occur. This was achieved by treating 7 human hemifaces with the Sihler modified staining protocol, which enables clear visualization of the course and distribution of nerves without the accidental displacement of these structures that can occur during classic dissection. The twigs of the ION can be classified into the usual 5 groups: inferior palpebral, innervating the lower eyelid in a fan-shaped area; external and internal nasal, reaching the nosewing and philtrum including the septal area between the nostrils, respectively; as well as medial and lateral superior labial, supplying the superior labial area from the midline to the mouth corner. Of particular note, the superior labial twigs fully innervated the infraorbital triangle formed by the infraorbital foramen, the most lateral point of the nosewing, and the mouth corner. In the superior 3-quarter area, the ION twigs made anastomoses with the buccal branches of the facial nerve, forming an infraorbital nervous plexus. The infraorbital triangle may be considered a dangerous zone with respect to the risk for iatrogenic complications associated with the various medical interventions such as implant placement. PMID:25329852

Yang, Hun-Mu; Won, Sung-Yoon; Lee, Young-Il; Kim, Hee-Jin; Hu, Kyung-Seok

2014-11-01

325

Root nutrient foraging.  

PubMed

During a plant's lifecycle, the availability of nutrients in the soil is mostly heterogeneous in space and time. Plants are able to adapt to nutrient shortage or localized nutrient availability by altering their root system architecture to efficiently explore soil zones containing the limited nutrient. It has been shown that the deficiency of different nutrients induces root architectural and morphological changes that are, at least to some extent, nutrient specific. Here, we highlight what is known about the importance of individual root system components for nutrient acquisition and how developmental and physiological responses can be coupled to increase nutrient foraging by roots. In addition, we review prominent molecular mechanisms involved in altering the root system in response to local nutrient availability or to the plant's nutritional status. PMID:25082891

Giehl, Ricardo F H; von Wirén, Nicolaus

2014-10-01

326

Combination of Acellular Nerve Graft and Schwann Cells-Like Cells for Rat Sciatic Nerve Regeneration  

PubMed Central

Objective. To investigate the effect of tissue engineering nerve on repair of rat sciatic nerve defect. Methods. Forty-five rats with defective sciatic nerve were randomly divided into three groups. Rats in group A were repaired by acellular nerve grafts only. Rats in group B were repaired by tissue engineering nerve. In group C, rats were repaired by autogenous nerve grafts. After six and twelve weeks, sciatic nerve functional index (SFI), neural electrophysiology (NEP), histological and transmission electron microscope observation, recovery ratio of wet weight of gastrocnemius muscle, regenerated myelinated nerve fibers number, nerve fiber diameter, and thickness of the myelin sheath were measured to assess the effect. Results. After six and twelve weeks, the recovery ratio of SFI and wet weight of gastrocnemius muscle, NEP, and the result of regenerated myelinated nerve fibers in groups B and C were superior to that of group A (P < 0.05), and the difference between groups B and C was not statistically significant (P > 0.05). Conclusion. The tissue engineering nerve composed of acellular allogenic nerve scaffold and Schwann cells-like cells can effectively repair the nerve defect in rats and its effect was similar to that of the autogenous nerve grafts. PMID:25114806

Gao, Songtao; Zheng, Yan; Cai, Qiqing; Deng, Zhansheng; Yao, Weitao; Wang, Jiaqiang; Wang, Xin; Zhang, Peng

2014-01-01

327

Effects of threshold displacement energy on defect production by displacement cascades in ?, ? and ?-LiAlO2  

NASA Astrophysics Data System (ADS)

Threshold displacement energy evaluation and a series of displacement cascade simulations in ?, ?, and ?-LiAlO2 were performed using molecular dynamics. Threshold displacement energy evaluations indicated that higher absolute ionic charge values and larger densities both increase threshold displacement energy. The displacement cascade simulations suggest that the influence of different crystal structures on the number of interstitial atoms generated in a displacement cascade is explainable almost entirely by the difference of the threshold displacement energy.

Tsuchihira, H.; Oda, T.; Tanaka, S.

2013-11-01

328

Anion-exchange displacement centrifugal partition chromatography.  

PubMed

Ion-exchange displacement chromatography has been adapted to centrifugal partition chromatography. The use of an ionic liquid, benzalkonium chloride, as a strong anion-exchanger has proven to be efficient for the preparative separation of phenolic acid regioisomers. Multigram quantities of a mixture of three hydroxycinnamic acid isomers were separated using iodide as a displacer. The displacement process was characterized by a trapezoidal profile of analyte concentration in the eluate with narrow transition zones. By taking advantage of the partition rules involved in support-free liquid-liquid chromatography, a numerical separation model is proposed as a tool for preliminary process validation and further optimization. PMID:15516108

Maciuk, Alexandre; Renault, Jean-Hugues; Margraff, Rodolphe; Trébuchet, Philippe; Zèches-Hanrot, Monique; Nuzillard, Jean-Marc

2004-11-01

329

Feasibility of Nerve Stimulator as a Supplemental Aid for Lumbar Transforaminal Epidural Block  

PubMed Central

Background The purpose of this study was to evaluate the clinical feasibility of an electric nerve stimulator in a lumbar transforaminal epidural block. Methods Using an electric nerve stimulator, transforaminal epidural blocks were performed in 105 segments of 49 patients who presented with lower back pain with radiating pain to lower extremities. The contrast medium was injected to delineate the nerve root after positioning an insulated needle at the intervertebral foramen under fluoroscopic guidance. Then, the nerve root was electrically stimulated with the insulated needle to confirm whether or not the same radiating pain was evoked. Results Of the 105 foraminal segments, the same radiating pain was evoked at 0.5 mAh in 47 segments (44.8%), at 1.0 mAh in 22 (21.0%), at 1.5 mAh in 3 (2.9%), at 2.0 mAh in 15 (14.3%), at 2.5 mAh in 4 (3.8%), and at 3.0 mAh in 5 (4.8%). No response was observed in 9 segments (8.6%). The fluoroscopy revealed successful positioning of the needle in the patients with an evoked radiating pain over 2.0 mAh. The visual analogue scale (VAS) obtained for pain improved from a mean of 7.5 to 2.7 after the block (p = 0.001). In the 9 cases without response to electrical stimulation, the patients showed an improvement on VAS from 7.8 to 3.4 (p= 0.008) also. Conclusions A nerve stimulator can help to predict the accuracy of needle positioning as a supplemental aid for a successful lumbar transforaminal epidural block. It is sufficient to initiate a proper stimulation amplitude of the nerve at 2 mAh. PMID:25177459

Kim, Dae Hee; Lim, Chae Hyun; Heo, Ju Yeong; Jang, Young Jae

2014-01-01

330

Local Anesthesia and Nerve Blocks  

Microsoft Academic Search

\\u000a Many inguino-scrotal procedures in urology can be performed under local anesthesia. Sometimes local anesthetics are used to\\u000a supplement post-operative pain relief in patients who had general anesthesia. The common nerve blocks are an inguinal block\\u000a for hernia repairs and inguinal orchidectomies, a cord block for vasectomies, and a penile block for circumcision and frenuloplasty.\\u000a The testis and scrotum are innervated

Hashim Hashim

331

Effect of microstructure and notch root radius on fracture toughness of an aluminum metal matrix composite  

NASA Technical Reports Server (NTRS)

Recent results on the effects of matrix aging condition (matrix temper) and notch root radius on the measured fracture toughness of a SiC particulate reinforced aluminum alloy are reviewed. Stress intensity factors at catastrophic fracture were obtained for both underaged and overaged composites reveal. The linear relation found between apparent fracture toughness and the square root of the notch root radius implies a linear dependence of the crack opening displacement on the notch root radius. The results suggest a strain controlled fracture process, and indicate that there are differences in the fracture micromechanisms of the two aging conditions.

Manoharan, M.; Lewandowski, J. J.

1989-01-01

332

Ultrasound imaging of the rabbit peroneal nerve.  

PubMed

Ultrasound imaging of peripheral nerves is increasingly used in the clinic for a wide range of applications. Although yet unapplied for experimental neuroscience, it also has potential value in this research area. This study explores the feasibility, possibilities and limitations of this technique in rabbits, with special focus on peripheral nerve regeneration after trauma. The peroneal nerve of 25 New Zealand White rabbits was imaged at varying time intervals after a crush lesion. The ultrasonic appearance of the nerve was determined, and recordings were validated with in vivo anatomy. Nerve swelling at the lesion site was estimated from ultrasound images and compared with anatomical parameters. The peroneal nerve could reliably be identified in all animals, and its course and anatomical variations agreed perfectly with anatomy. Nerve diameters from ultrasound were related to in vivo diameters (p < 0.001, R(2) = 77%), although the prediction interval was rather wide. Nerve thickenings could be visualized and preliminary results indicate that ultrasound can differentiate between neuroma formation and external nerve thickening. The value of the technique for experimental neuroscience is discussed. We conclude that ultrasound imaging of the rabbit peroneal nerve is feasible and that it is a promising tool for different research areas within the field of experimental neuroscience. PMID:16279986

de Kool, B S; van Neck, Johan W; Blok, Joleen H; Walbeehm, Erik T; Hekking, Ineke; Visser, Gerhard H

2005-12-01

333

Inferior alveolar nerve block: Alternative technique  

PubMed Central

Background: Inferior alveolar nerve block (IANB) is a technique of dental anesthesia, used to produce anesthesia of the mandibular teeth, gingivae of the mandible and lower lip. The conventional IANB is the most commonly used the nerve block technique for achieving local anesthesia for mandibular surgical procedures. In certain cases, however, this nerve block fails, even when performed by the most experienced clinician. Therefore, it would be advantageous to find an alternative simple technique. Aim and Objective: The objective of this study is to find an alternative inferior alveolar nerve block that has a higher success rate than other routine techniques. To this purpose, a simple painless inferior alveolar nerve block was designed to anesthetize the inferior alveolar nerve. Materials and Methods: This study was conducted in Oral surgery department of Vinayaka Mission's dental college Salem from May 2009 to May 2011. Five hundred patients between the age of 20 years and 65 years who required extraction of teeth in mandible were included in the study. Out of 500 patients 270 were males and 230 were females. The effectiveness of the IANB was evaluated by using a sharp dental explorer in the regions innervated by the inferior alveolar, lingual, and buccal nerves after 3, 5, and 7 min, respectively. Conclusion: This study concludes that inferior alveolar nerve block is an appropriate alternative nerve block to anesthetize inferior alveolar nerve due to its several advantages.

Thangavelu, K.; Kannan, R.; Kumar, N. Senthil

2012-01-01

334

REVERSE DISPLACEMENT ANALYSIS FOR TENSEGRITY STRUCTURES  

E-print Network

REVERSE DISPLACEMENT ANALYSIS FOR TENSEGRITY STRUCTURES By TUNG MINH TRAN A THESIS PRESENTED INTRODUCTION.........................................................................1 2 THREE-THREE TENSEGRITY-THREE TENSEGRITY PLATFORMS WITH AN APPLIED EXTERNAL WRENCH....................................... 28 Plücker

Florida, University of

335

Seismic transducer measures small horizontal displacements  

NASA Technical Reports Server (NTRS)

Pendular seismic transducer mounted on base plate measures small horizontal displacements of structures subjected to vibration where no fixed reference point is available. Enclosure of transducer in transparent plastic case prevents air currents from disturbing the pendulum balance.

Greenwood, T. L.

1965-01-01

336

Scale model studies of displacement ventilation  

E-print Network

Displacement ventilation is an air conditioning method that provides conditioned air to indoor environments with the goal to improve air quality while reducing energy consumption. This study investigates the performance ...

Okutan, Galip Mehmet

1995-01-01

337

Root hydrotropism: an update.  

PubMed

While water shortage remains the single-most important factor influencing world agriculture, there are very few studies on how plants grow in response to water potential, i.e., hydrotropism. Terrestrial plant roots dwell in the soil, and their ability to grow and explore underground requires many sensors for stimuli such as gravity, humidity gradients, light, mechanical stimulations, temperature, and oxygen. To date, extremely limited information is available on the components of such sensors; however, all of these stimuli are sensed in the root cap. Directional growth of roots is controlled by gravity, which is fixed in direction and intensity. However, other environmental factors, such as water potential gradients, which fluctuate in time, space, direction, and intensity, can act as a signal for modifying the direction of root growth accordingly. Hydrotropism may help roots to obtain water from the soil and at the same time may participate in the establishment of the root system. Current genetic analysis of hydrotropism in Arabidopsis has offered new players, mainly AHR1, NHR1, MIZ1, and MIZ2, which seem to modulate how root caps sense and choose to respond hydrotropically as opposed to other tropic responses. Here we review the mechanism(s) by which these genes and the plant hormones abscisic acid and cytokinins coordinate hydrotropism to counteract the tropic responses to gravitational field, light or touch stimuli. The biological consequence of hydrotropism is also discussed in relation to water stress avoidance. PMID:23258371

Cassab, Gladys I; Eapen, Delfeena; Campos, María Eugenia

2013-01-01

338

Atmospheric pressure loading displacement of SLR stations  

NASA Astrophysics Data System (ADS)

This paper addresses the local displacement at ground stations of the world-wide Satellite Laser Ranging (SLR) network induced by atmospheric pressure variations. Since currently available modelling options do not satisfy the requirements for the target application (real-time availability, complete coverage of SLR network), a new representation is developed. In a first step, the 3-dimensional displacements are computed from a 6-hourly grid of 1°×1° global pressure data obtained from the ECMWF, for the period 1997-2002. After having been converted into pressure anomalies, this pressure grid is propagated into horizontal and vertical station displacements using Green's functions and integrating contributions covering the entire globe; oceans are assumed to follow the inverted barometer (IB) approximation. In the next step, a linear regression model is developed for each station that approximates the time-series of the predicted vertical displacements as well as possible; this regression model relates the vertical displacement of a particular station to the local (and instantaneous) pressure anomaly. It is shown that such a simple model may represent the actual vertical displacements with an accuracy of better than 1 mm; horizontal displacements are shown to be negligible. Finally, the regression model is tested on actual SLR data on the satellites LAGEOS-1 and LAGEOS-2, covering the period January 2002 until April 2003 (inclusive). Also, two model elements are shown to be potential risk factors: the global pressure field representation (for the convolution method) and the local reference pressure (for the regression method). The inclusion of the atmospheric pressure displacement model gives improvements on most of the elements of the computations, although the effects are smaller than expected since the nominal effect is absorbed by solved-for satellite parameters.

Bock, D.; Noomen, R.; Scherneck, H.-G.

2005-04-01

339

High Precision Displacement Measurement Using Fiber Optics  

Microsoft Academic Search

We describe laboratory experiments with a fiber-optic sensor employing a chirped laser that detects, with 20-30 micrometer accuracy, displacements of a remote reflective target at distance of 200-500 mm. The requirements of chirp linearity and laser coherence in order to achieve this sensitivity are elaborated. This sensor can be employed for remotely sensing minute displacements of objects in harsh environments,

G Berkovic; S Rotter; Walter Scandale; E Shafir; Ezio Todesco

2002-01-01

340

Nanofibrous nerve conduits for repair of 30-mm-long sciatic nerve defects  

PubMed Central

It has been confirmed that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit can promote peripheral nerve regeneration in rats. However, its efficiency in repair of over 30-mm-long sciatic nerve defects needs to be assessed. In this study, we used a nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit to bridge a 30-mm-long gap in the rat sciatic nerve. At 4 months after nerve conduit implantation, regenerated nerves were cally observed and histologically assessed. In the nanofibrous graft, the rat sciatic nerve trunk had been reconstructed by restoration of nerve continuity and formation of myelinated nerve fiber. There were Schwann cells and glial cells in the regenerated nerves. Masson's trichrome staining showed that there were no pathological changes in the size and structure of gastrocnemius muscle cells on the operated side of rats. These findings suggest that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit is suitable for repair of long-segment sciatic nerve defects.

Biazar, Esmaeil; Keshel, Saeed Heidari; Pouya, Majid; Rad, Hadi; Nava, Melody Omrani; Azarbakhsh, Mohammad; Hooshmand, Shirin

2013-01-01

341

Displacement sensor for indoor machine calibrations.  

PubMed

This paper presents a simple displacement sensor for indoor machine calibrations. The sensor, which is placed in the path of a diverging laser beam, consists of two plane mirror pieces laterally displaced with the line joining their centers initially held perpendicular to the optical axis of the beam during the displacement of the sensor with one of the mirrors always traveling along the optical axis of the laser beam. The optical signals from the two mirrors are combined and a simple detector at the interference plane counts the fringes during the sensor displacement. The sensor could be mounted on the moving head of any mechanical machine, e.g., the lathe machine for displacement calibration. The device has been tested over a range of 10 cm beyond a distance of 150 cm from a diverging laser source giving an accuracy of 1.1015 ?m. Theoretical modeling, simulation, and experimental results are presented which establish that the proposed sensor can be used as a promising displacement measuring device. PMID:23736230

Mudassar, Asloob Ahmad; Butt, Saira

2013-05-20

342

Tsunami mortality and displacement in Aceh province, Indonesia  

E-print Network

Tsunami mortality and displacement in Aceh province, Indonesia Abdur Rofi, MA Mercy Corps Indonesia, Indonesia, Shannon Doocy, PhD Research Associate, Johns Hopkins Bloomberg School of Public Health, US. Keywords: displacement, internally displaced persons (IDPs), Indonesia, mortality, tsunami Introduction

Scharfstein, Daniel

343

Intercostal nerve conduction study in man.  

PubMed Central

A new surface technique for the conduction study of the lower intercostal nerves has been developed and applied to 30 normal subjects. The problem of the short available nerve segment of the intercostal nerves and the bizzare compound motor action potential (CMAP) of inconsistent latency while recording over the intercostal muscles, is overcome by applying recording electrodes over the rectus abdominis muscle and stimulating the nerves at two points at a fair distance away. With the use of multiple recording sites over the rectus abdominis, the motor points for different intercostal nerves were delineated. CMAP of reproducible latencies and waveforms with sharp take-off points were obtained. Conduction velocity of the intercostal nerves could be determined. PMID:2526200

Pradhan, S; Taly, A

1989-01-01

344

Intercostal nerve conduction study in man.  

PubMed

A new surface technique for the conduction study of the lower intercostal nerves has been developed and applied to 30 normal subjects. The problem of the short available nerve segment of the intercostal nerves and the bizzare compound motor action potential (CMAP) of inconsistent latency while recording over the intercostal muscles, is overcome by applying recording electrodes over the rectus abdominis muscle and stimulating the nerves at two points at a fair distance away. With the use of multiple recording sites over the rectus abdominis, the motor points for different intercostal nerves were delineated. CMAP of reproducible latencies and waveforms with sharp take-off points were obtained. Conduction velocity of the intercostal nerves could be determined. PMID:2526200

Pradhan, S; Taly, A

1989-06-01

345

Saphenous nerve innervation of the medial ankle  

PubMed Central

Background The distal saphenous nerve is commonly known to provide cutaneous innervation of the medial side of the ankle and distally to the base of the great toe. We hypothesize that the saphenous nerve innervates the periosteum of the medial malleolus and joint capsule. Methods Five fresh limbs were dissected and the saphenous nerve was traced distally with magnification. The medial malleolus, talus, and soft tissue were fixed in formaldehyde, decalcified, and embedded in paraffin and sectioned. Histologic slides were then prepared using S100 antibody nerve stains. Results Histologic slides were examined and myelinated nerves could be observed within the medial capsule and periosteum in all the specimens. Conclusion We have demonstrated that the saphenous nerve innervates the periosteum of the medial malleolus and joint capsule. PMID:23630434

Clendenen, Steven R; Whalen, Joseph L

2013-01-01

346

Satellite cells of sensory neurons after various types of sciatic nerve trauma in the rat.  

PubMed

Sciatic nerve crushing, transection, and ligation models were used in rats to study the reactions of and changes in the numbers of satellite cells (SC) in spinal dorsal root ganglia in the lumbar segment. Nerve transection was followed by the appearance of neurons surrounded by two layers of SC. The thickness of SC processes and the areas of contacts with neurons increased as a result of invaginations into neuron perikarya. After nerve ligation, SC and their processes were located around parts of large and intermediate neurons in several tightly appressed layers; the area of contact between SC and neuron perikarya showed increased development of invaginations such that lamellar structures appeared in the SC cytoplasm, along with contacts with SC processes surrounding neighboring neurons. The greatest increases in SC numbers were seen after ligation of the nerve. Transection was followed by increases in the numbers of small and intermediate neurons surrounded by vimentin-positive SC. The number of large neurons surrounded by these cells decreased. At all time points following ligation of the nerve, all neurons in the study ganglia were surrounded by vimentin-positive SC. Post-traumatic changes in structure and numbers differed in SC associated with sensory neurons of individual size populations and depended on the type of trauma applied to efferent conductors. PMID:20532986

Arkhipova, S S; Raginov, I S; Mukhitov, A R; Chelyshev, Y A

2010-07-01

347

Fibrolipoma of multiple nerves in the wrist.  

PubMed

We report fibrolipoma involving the median nerve, its palmar cutaneous branch as well as the ulnar nerve in the same hand of a 25-year-old woman. The patient presented with a lump in the wrist with signs of carpal tunnel syndrome. Multiple nerve involvement was detected on magnetic resonance imaging and further confirmed at surgical exploration and decompression. Imaging is recommended in the management of an unusual lump in the wrist. PMID:19710960

Pang, H N; Puhaindran, M; Yong, F C

2009-08-01

348

Transsartorial approach for saphenous nerve block  

Microsoft Academic Search

Blockade of conduction in the saphenous nerve is important in providing surgical anaesthesia in the lower leg. Unfortunately,\\u000a previously described techniques have lacked clinical effectiveness in practice. We developed a transsartorial approach for\\u000a conduction block of the saphenous nerve. We first confirmed its potential clinical utility in 12 cadaveric specimens by demonstrating\\u000a that the saphenous nerve was consistently stained by

Michael van der Wal; Scott A. Lang; Ray W. Yip

1993-01-01

349

MR neurography of sciatic nerve injection injury  

Microsoft Academic Search

We report on magnetic resonance neurography (MRN) as a supplementary diagnostic tool in sciatic nerve injection injury. The\\u000a object of the study was to test if T2-weighted (w) contrast within the sciatic nerve serves as an objective criterion for\\u000a sciatic injection injury. Three patients presented with acute sensory and\\/or motor complaints in the distribution of the sciatic\\u000a nerve after dorsogluteal

Mirko Pham; Carsten Wessig; Jörg Brinkhoff; Karlheinz Reiners; Guido Stoll; Martin Bendszus

2011-01-01

350

Tumors of the peripheral nerves and plexuses  

Microsoft Academic Search

Opinion statement  Peripheral nerve tumors are a diverse group of lesions histologically and in their clinical behavior. The genetic disorders\\u000a neurofibromatosis type 1 and 2 and schwannomatosis are significant risk factors for the development of peripheral nerve tumors.\\u000a An understanding of these disorders is important in allowing appropriate management. Active treatment of peripheral nerve\\u000a tumors is reserved for lesions that are

Jason H. Huang; Victoria E. Johnson; Eric L. Zager

2006-01-01

351

Mandibular nerve entrapment in the infratemporal fossa  

Microsoft Academic Search

The posterior trunk of the mandibular nerve (V3) comprises of three main branches. Various anatomic structures may entrap and potentially compress the mandibular nerve branches.\\u000a A usual position of mandibular nerve (MN) compression is the infratemporal fossa (ITF) which is one of the most difficult\\u000a regions of the skull base to access surgically. The anatomical positions of compression are: the

Maria N. PiagkouT; T. Demesticha; G. Piagkos; G. Androutsos; P. Skandalakis

2011-01-01

352

Tissue engineering and peripheral nerve regeneration (III)  

Microsoft Academic Search

The biodegradation rate and biocompatibility of poly (d, \\/ -lactide) (PDLLA)in vivo were evaluated. The aim of this study was to establish a nerve guide constructed by the PDLLA with 3-D microenvironment and\\u000a to repair a 10 mm of sciatic nerve gap in rats. The process of the nerve regeneration was investigated by histological assessment,\\u000a electrophysiological examination, and determination of

Shenguo Wang; Jianwei Hou; Jianzhong Bei; Yongqiang Zhao

2001-01-01

353

[Iatrogenic surgical injuries of the peripheral nerves].  

PubMed

Iatrogenic nerve injuries in operative area are undesirable but relatively common complications in relation to the total number of nerve injuries. These injuries are mostly caused by objective factors, especially by the nature of surgical lesion. Unfortunately, the role of surgeon is not irrelevant in large number of cases. The authors analyze a series of 39 iatrogenic surgical nerve injuries and the results of 30 repaired cases. PMID:1792573

Pajevi?, N; Grujici?, D; Samardzi?, M

1991-01-01

354

Evaluation of recurrent laryngeal nerve monitoring in thyroid surgery  

Microsoft Academic Search

AimThyroidectomy creates a potential risk for all parathyroid glands and nerves. Nerve identification has decreased the rates of nerve injury during thyroidectomy. Intraoperative nerve monitoring (IONM) has been used as an adjunct to the visual identification of the nerve. The aim of this clinical trial is to evaluate the effect of the identification time of RLN during thyroidectomy using IONM.

Serkan Sar?; Ye?im Erbil; Aziz Sümer; Orhan Agcaoglu; Adem Bayraktar; Halim Issever; Selcuk Ozarmagan

2010-01-01

355

The Nerve of Henle: An Anatomic and Immunohistochemical Study  

Microsoft Academic Search

The topography of the nerve of Henle was reviewed. Fifty-two human cadaveric upper extremities were studied. In 30 (58%) the nerve was well defined; in 22 (42%) its origin from the ulnar nerve was unidentifiable. The palmar cutaneous branch of the ulnar nerve separated from the ulnar nerve 5 to 11 cm distal to the medial epicondyle of the humerus

Brigitta Balogh; Julia Valencak; Michael Vesely; Martina Flammer; Helmut Gruber; Hildegunde Piza-Katzer

1999-01-01

356

Calcium Signaling in Intact Dorsal Root Ganglia  

PubMed Central

Background Ca2+ is the dominant second messenger in primary sensory neurons. In addition, disrupted Ca2+ signaling is a prominent feature in pain models involving peripheral nerve injury. Standard cytoplasmic Ca2+ recording techniques use high K+ or field stimulation and dissociated neurons. To compare findings in intact dorsal root ganglia, we used a method of simultaneous electrophysiologic and microfluorimetric recording. Methods Dissociated neurons were loaded by bath-applied Fura-2-AM and subjected to field stimulation. Alternatively, we adapted a technique in which neuronal somata of intact ganglia were loaded with Fura-2 through an intracellular microelectrode that provided simultaneous membrane potential recording during activation by action potentials (APs) conducted from attached dorsal roots. Results Field stimulation at levels necessary to activate neurons generated bath pH changes through electrolysis and failed to predictably drive neurons with AP trains. In the intact ganglion technique, single APs produced measurable Ca2+ transients that were fourfold larger in presumed nociceptive C-type neurons than in nonnociceptive A?-type neurons. Unitary Ca2+ transients summated during AP trains, forming transients with amplitudes that were highly dependent on stimulation frequency. Each neuron was tuned to a preferred frequency at which transient amplitude was maximal. Transients predominantly exhibited monoexponential recovery and had sustained plateaus during recovery only with trains of more than 100 APs. Nerve injury decreased Ca2+ transients in C-type neurons, but increased transients in A?-type neurons. Conclusions Refined observation of Ca2+ signaling is possible through natural activation by conducted APs in undissociated sensory neurons and reveals features distinct to neuronal types and injury state. PMID:20526180

Gemes, Geza; Rigaud, Marcel; Koopmeiners, Andrew S.; Poroli, Mark J.; Zoga, Vasiliki; Hogan, Quinn H.

2013-01-01

357

GFR?1 released by nerves enhances cancer cell perineural invasion through GDNF-RET signaling  

PubMed Central

The ability of cancer cells to invade along nerves is associated with aggressive disease and diminished patient survival rates. Perineural invasion (PNI) may be mediated by nerve secretion of glial cell line-derived neurotrophic factor (GDNF) attracting cancer cell migration through activation of cell surface Ret proto-oncogene (RET) receptors. GDNF family receptor (GFR)?1 acts as coreceptor with RET, with both required for response to GDNF. We demonstrate that GFR?1 released by nerves enhances PNI, even in the absence of cancer cell GFR?1 expression. Cancer cell migration toward GDNF, RET phosphorylation, and MAPK pathway activity are increased with exposure to soluble GFR?1 in a dose-dependent fashion. Dorsal root ganglia (DRG) release soluble GFR?1, which potentiates RET activation and cancer cell migration. In vitro DRG coculture assays of PNI show diminished PNI with DRG from GFR?1+/? mice compared with GFR?1+/+ mice. An in vivo murine model of PNI demonstrates that cancer cells lacking GFR?1 maintain an ability to invade nerves and impair nerve function, whereas those lacking RET lose this ability. A tissue microarray of human pancreatic ductal adenocarcinomas demonstrates wide variance of cancer cell GFR?1 expression, suggesting an alternate source of GFR?1 in PNI. These findings collectively demonstrate that GFR?1 released by nerves enhances PNI through GDNF-RET signaling and that GFR?1 expression by cancer cells enhances but is not required for PNI. These results advance a mechanistic understanding of PNI and implicate the nerve itself as a key facilitator of this adverse cancer cell behavior. PMID:24778213

He, Shuangba; Chen, Chun-Hao; Chernichenko, Natalya; He, Shizhi; Bakst, Richard L.; Barajas, Fernando; Deborde, Sylvie; Allen, Peter J.; Vakiani, Efsevia; Yu, Zhenkun; Wong, Richard J.

2014-01-01

358

GFR?1 released by nerves enhances cancer cell perineural invasion through GDNF-RET signaling.  

PubMed

The ability of cancer cells to invade along nerves is associated with aggressive disease and diminished patient survival rates. Perineural invasion (PNI) may be mediated by nerve secretion of glial cell line-derived neurotrophic factor (GDNF) attracting cancer cell migration through activation of cell surface Ret proto-oncogene (RET) receptors. GDNF family receptor (GFR)?1 acts as coreceptor with RET, with both required for response to GDNF. We demonstrate that GFR?1 released by nerves enhances PNI, even in the absence of cancer cell GFR?1 expression. Cancer cell migration toward GDNF, RET phosphorylation, and MAPK pathway activity are increased with exposure to soluble GFR?1 in a dose-dependent fashion. Dorsal root ganglia (DRG) release soluble GFR?1, which potentiates RET activation and cancer cell migration. In vitro DRG coculture assays of PNI show diminished PNI with DRG from GFR?1(+/-) mice compared with GFR?1(+/+) mice. An in vivo murine model of PNI demonstrates that cancer cells lacking GFR?1 maintain an ability to invade nerves and impair nerve function, whereas those lacking RET lose this ability. A tissue microarray of human pancreatic ductal adenocarcinomas demonstrates wide variance of cancer cell GFR?1 expression, suggesting an alternate source of GFR?1 in PNI. These findings collectively demonstrate that GFR?1 released by nerves enhances PNI through GDNF-RET signaling and that GFR?1 expression by cancer cells enhances but is not required for PNI. These results advance a mechanistic understanding of PNI and implicate the nerve itself as a key facilitator of this adverse cancer cell behavior. PMID:24778213

He, Shuangba; Chen, Chun-Hao; Chernichenko, Natalya; He, Shizhi; Bakst, Richard L; Barajas, Fernando; Deborde, Sylvie; Allen, Peter J; Vakiani, Efsevia; Yu, Zhenkun; Wong, Richard J

2014-05-13

359

Use new PLGL-RGD-NGF nerve conduits for promoting peripheral nerve regeneration  

PubMed Central

Background Nerve conduits provide a promising strategy for peripheral nerve injury repair. However, the efficiency of nerve conduits to enhance nerve regeneration and functional recovery is often inferior to that of autografts. Nerve conduits require additional factors such as cell adhesion molecules and neurotrophic factors to provide a more conducive microenvironment for nerve regeneration. Methods In the present study, poly{(lactic acid)-co-[(glycolic acid)-alt-(L-lysine)]} (PLGL) was modified by grafting Gly-Arg-Gly-Asp-Gly (RGD peptide) and nerve growth factor (NGF) for fabricating new PLGL-RGD-NGF nerve conduits to promote nerve regeneration and functional recovery. PLGL-RGD-NGF nerve conduits were tested in the rat sciatic nerve transection model. Rat sciatic nerves were cut off to form a 10 mm defect and repaired with the nerve conduits. All of the 32 Wistar rats were randomly divided into 4 groups: group PLGL-RGD-NGF, group PLGL-RGD, group PLGL and group autograft. At 3 months after surgery, the regenerated rat sciatic nerve was evaluated by footprint analysis, electrophysiology, and histologic assessment. Experimental data were processed using the statistical software SPSS 10.0. Results The sciatic function index value of groups PLGL-RGD-NGF and autograft was significantly higher than those of groups PLGL-RGD and PLGL. The nerve conduction velocities of groups PLGL-RGD-NGF and autograft were significantly faster than those of groups PLGL-RGD and PLGL. The regenerated nerves of groups PLGL-RGD-NGF and autograft were more mature than those of groups PLGL-RGD and PLGL. There was no significant difference between groups PLGL-RGD-NGF and autograft. Conclusions PLGL-RGD-NGF nerve conduits are more effective in regenerating nerves than both PLGL-RGD nerve conduits and PLGL nerve conduits. The effect is as good as that of an autograft. This work established the platform for further development of the use of PLGL-RGD-NGF nerve conduits for clinical nerve repair. PMID:22776032

2012-01-01

360

Dural ectasia of the optic nerve sheath  

PubMed Central

Optic nerve dural ectasia is a rare cause of optic nerve sheath enlargement due to the accumulation of CSF around the optic nerve with no associated pathology. It diagnosed by MRI studies and can follow benign or sometimes an unfavorable course. We describe the case of a 24-day-old female referred for a visual blurring, which we diagnosed as a dural ectasia of the optic nerve sheath by MRI and confirmed in surgical intervention. We present this case report to illustrate the classic imaging features of the disease. PMID:25374645

Kacem, Hanane Hadj; Hammani, Lehcen; Ajana, Ali; Nassar, Itimad

2014-01-01

361

Raman microspectroscopy for visualization of peripheral nerves  

NASA Astrophysics Data System (ADS)

The peripheral nervous system plays an important role in motility, sensory, and autonomic functions of the human body. Preservation of peripheral nerves in surgery is essential for improving quality of life of patients. To preserve peripheral nerves, detection of ne peripheral nerves that cannot be identi ed by human eye or under white light imaging is necessary. In this study, we sought to provide a proof-of-principle demonstration of a label-free detection technique of peripheral nerve tissues against adjacent tissues that employs spontaneous Raman microspectroscopy. A line-illumination confocal Raman microscope was used for the experiment. A laser operating at the wavelength of 532 nm was used as an excitation laser light. We obtained Raman spectra of peripheral nerve, brous connective tissue, skeletal muscle, blood vessel, and adipose tissue of Wistar rats, and extracted speci c spectral features of peripheral nerves and adjacent tissues. By applying multivariate image analysis, peripheral nerves were clearly detected against adjacent tissues without any preprocessing neither xation nor staining. These results suggest the potential of the Raman spectroscopic observation for noninvasive and label-free nerve detection, and we expect this method could be a key technique for nerve-sparing surgery.

Minamikawa, Takeo; Harada, Yoshinori; Koizumi, Noriaki; Takamatsu, Tetsuro

2013-02-01

362

Study on Variant Anatomy of Sciatic Nerve  

PubMed Central

Introduction: Sciatic Nerve (SN) is the nerve of the posterior compartment of thigh formed in the pelvis from the ventral rami of the L4 to S3 spinal nerves. It leaves the pelvis via the greater sciatic foramen below piriformis and divides into Common Peroneal Nerve (CPN) and Tibial Nerve (TN) at the level of the upper angle of the popliteal fossa. Higher division of the sciatic nerve is the most common variation where the TN and CPN may leave the pelvis through different routes. Such variation may lead to compression of the nerve and lead to Non-discogenic sciatica. Materials and Methods: Fifty lower limbs were used for the study from Department of Anatomy, J.J.M.M.C Davangere, Karnataka, India. Observation and Results: In our study on 25 cadavers (50 lower limbs), we have observed 4 (8 %) lower limbs high division of sciatic nerve was noted. High division of sciatic nerve in the back of thigh was noted in one specimen (2%), while high division within the pelvis was noted in 3 specimens (6%), while in 46 (92%) it occurred outside the pelvis. Conclusion: Knowledge regarding such variation and differences in the course of SN is important for the surgeons to plan for various surgical interventions pertaining to the gluteal region. The variant anatomy of SN may cause piriformis syndrome and failure of SN block. Hence present study is undertaken to know the level of division, exit, course, relationship to piriformis and variations in the branching pattern of SN.

V, Sangeetha

2014-01-01

363

Tissue engineered constructs for peripheral nerve surgery  

PubMed Central

Summary Background Tissue engineering has been defined as “an interdisciplinary field that applies the principles of engineering and life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function or a whole organ”. Traumatic peripheral nerve injury resulting in significant tissue loss at the zone of injury necessitates the need for a bridge or scaffold for regenerating axons from the proximal stump to reach the distal stump. Methods A review of the literature was used to provide information on the components necessary for the development of a tissue engineered peripheral nerve substitute. Then, a comprehensive review of the literature is presented composed of the studies devoted to this goal. Results Extensive research has been directed toward the development of a tissue engineered peripheral nerve substitute to act as a bridge for regenerating axons from the proximal nerve stump seeking the distal nerve. Ideally this nerve substitute would consist of a scaffold component that mimics the extracellular matrix of the peripheral nerve and a cellular component that serves to stimulate and support regenerating peripheral nerve axons. Conclusions The field of tissue engineering should consider its challenge to not only meet the autograft “gold standard” but also to understand what drives and inhibits nerve regeneration in order to surpass the results of an autograft. PMID:24385980

Johnson, P. J.; Wood, M. D.; Moore, A. M.; Mackinnon, S. E.

2013-01-01

364

Roots and Extremal Points  

NASA Astrophysics Data System (ADS)

In computational physics very often roots and local extrema of a function have to be determined. In one dimension bisection is a very robust but rather inefficient root finding method. If a good starting point close to the root is available and the function is smooth enough, the Newton-Raphson method converges much faster. Special strategies are necessary to find roots of not so well behaved functions or higher order roots. The combination of bisection and interpolation as by the methods of Dekker, Brent and more recently Chandrupatla provides generally applicable algorithms. In multidimensions Quasi-Newton methods are a good choice. Whereas local extrema can be found as the roots of the gradient, at least in principle, direct optimization can be more efficient. In one dimension the ternary search method or Brent's more efficient golden section search method can be used. In multidimensions the class of direction set search methods is very popular which includes the methods of steepest descent and conjugate gradients, the Newton-Raphson method and, if calculation of the full Hessian matrix is too expensive, the Quasi-Newton methods.

Scherer, Philipp O. J.

365

Unusual cases of cervical nerves schwannomas: phrenic and vagus nerve involvement  

Microsoft Academic Search

Benign neurogenic tumors (neurilemmoma) arising from the cervical phrenic or vagus nerve are relatively rare. These lesions are benign, asymptomatic and incidentally found. We describe two cases considering different surgical techniques adopted. In the case of phrenic nerve schwannoma we performed a total excision of the tumor including the maternal nerve fiber to prevent tumor recurrence, also in regard to

Emilio Mevio; E. Gorini; M. Sbrocca; L. Artesi; M. Mullace; A. Castelli; L. Migliorini

2003-01-01

366

Heparin-Binding-Affinity-Based Delivery Systems Releasing Nerve Growth Factor Enhance Sciatic Nerve Regeneration  

Microsoft Academic Search

The controlled delivery of nerve growth factor (NGF) to the peripheral nervous system has been shown to enhance nerve regeneration following injury, although the effect of release rate has not been previously studied with an affinity-based delivery system (DS). The goal of this research was to determine if the binding site affinity of the DS affected nerve regeneration in vivo

Matthew D. Wood; Daniel Hunter; Susan E. Mackinnon; Shelly E. Sakiyama-Elbert

2010-01-01

367

The management of the displaced medial wall in complex acetabular fractures using plates and additional cerclage.  

PubMed

Reduction for displaced quadrilateral plates in complicated acetabular fractures is difficult and requires wide exposure. The purpose of this study is to assess the usefulness of the additional cable in this complicated fracture and to evaluate the potential danger of compressing the superior gluteal artery and nerve with cable application. We evaluated 31 hips (these included 25 hips with fractures of both columns, two posterior wall and column fractures, three anterior column and posterior hemitransverse fractures, and one high T-shaped fracture) with an average six-year follow-up. Clinical outcomes were evaluated using a modification of the Matta grading system and radiographic arthritic grades. We assessed the postoperative clinical outcomes in relation with other variables such as anatomical reduction, delayed operation, seagull sign, and femoral head injuries. We determined whether the superior gluteal artery and nerve were compressed by cerclage with the help of femoral angiography and EMG. Clinical outcomes were graded as very good to excellent for 18 patients, good for five, fair for three ?and poor for five. Preoperative femoral head injury (P = 0.011), a seagull sign (P = 0.001), poor reduction (P = 0.015), and delayed reduction (P = 0.05) were found to statistically influence clinical results. We found that there were no injuries to the superior gluteal artery and nerve in spite of using a cable. Cerclage methods can be useful for initial reduction of displaced medial plates in acetabular fractures. These methods reduce operation time and blood loss as compared with other methods. PMID:23559194

Park, Myung-sik; Yoon, Sun Jung; Park, Jong-hyuk; Choi, Seung-min

2013-01-01

368

Root architecture impacts on root decomposition rates in switchgrass  

NASA Astrophysics Data System (ADS)

Roots strongly contribute to soil organic carbon accrual, but the rate of soil carbon input via root litter decomposition is still uncertain. Root systems are built up of roots with a variety of different diameter size classes, ranging from very fine to very coarse roots. Since fine roots have low C:N ratios and coarse roots have high C:N ratios, root systems are heterogeneous in quality, spanning a range of different C:N ratios. Litter decomposition rates are generally well predicted by litter C:N ratios, thus decomposition of roots may be controlled by the relative abundance of fine versus coarse roots. With this study we asked how root architecture (i.e. the relative abundance of fine versus coarse roots) affects the decomposition of roots systems in the biofuels crop switchgrass (Panicum virgatum L.). To understand how root architecture affects root decomposition rates, we collected roots from eight switchgrass cultivars (Alamo, Kanlow, Carthage, Cave-in-Rock, Forestburg, Southlow, Sunburst, Blackwell), grown at FermiLab (IL), by taking 4.8-cm diameter soil cores from on top of the crown and directly next to the crown of individual plants. Roots were carefully excised from the cores by washing and analyzed for root diameter size class distribution using WinRhizo. Subsequently, root systems of each of the plants (4 replicates per cultivar) were separated in 'fine' (0-0.5 mm), 'medium' (0.5-1 mm) and 'coarse' roots (1-2.5 mm), dried, cut into 0.5 cm (medium and coarse roots) and 2 mm pieces (fine roots), and incubated for 90 days. For each of the cultivars we established five root-treatments: 20g of soil was amended with 0.2g of (1) fine roots, (2) medium roots, (3) coarse roots, (4) a 1:1:1 mixture of fine, medium and coarse roots, and (5) a mixture combining fine, medium and coarse roots in realistic proportions. We measured CO2 respiration at days 1, 3, 7, 15, 30, 60 and 90 during the experiment. The 13C signature of the soil was -26‰, and the 13C signature of plants was -12‰, enabling us to differentiate between root-derived C and native SOM-C respiration. We found that the relative abundance of fine, medium and coarse roots were significantly different among cultivars. Root systems of Alamo, Kanlow and Cave-in-Rock were characterized by a large abundance of coarse-, relative to fine roots, whereas Carthage, Forestburg and Blackwell had a large abundance of fine, relative to coarse roots. Fine roots had a 28% lower C:N ratio than medium and coarse roots. These differences led to different root decomposition rates. We conclude that root architecture should be taken into account when predicting root decomposition rates; enhanced understanding of the mechanisms of root decomposition will improve model predictions of C input to soil organic matter.

de Graaff, M.; Schadt, C.; Garten, C. T.; Jastrow, J. D.; Phillips, J.; Wullschleger, S. D.

2010-12-01

369

The "Green" Root Beer Laboratory  

ERIC Educational Resources Information Center

No, your students will not be drinking green root beer for St. Patrick's Day--this "green" root beer laboratory promotes environmental awareness in the science classroom, and provides a venue for some very sound science content! While many science classrooms incorporate root beer-brewing activities, the root beer lab presented in this article has…

Clary, Renee; Wandersee, James

2010-01-01

370

Detergent-free Decellularized Nerve Grafts for Long-gap Peripheral Nerve Reconstruction  

PubMed Central

Background: Long-gap peripheral nerve defects arising from tumor, trauma, or birth-related injuries requiring nerve reconstruction are currently treated using nerve autografts and nerve allografts. Autografts are associated with limited supply and donor-site morbidity. Allografts require administration of transient immunosuppressants, which has substantial associated risks. To overcome these limitations, we investigated the use of detergent-free decellularized nerve grafts to reconstruct long-gap nerve defects in a rodent model and compared it with existing detergent processing techniques. Methods: Nerve grafts were harvested from the sciatic nerves of 9 donor rats. Twenty-four recipient rats were divided into 4 groups (6 animals per group): (1) nerve grafts (NG, positive control), (2) detergent-free decellularized (DFD) grafts, (3) detergent decellularized grafts, and (4) silicone tube conduits (negative control). Each recipient rat had a 3.5-cm graft or conduit sutured across a sciatic nerve transection injury. All animals were harvested at 12 weeks postimplantation for functional muscle analysis and nerve histomorphometry. Results: Histomorphometry results indicated maximum growth in NG when compared with other groups. DFD and detergent decellularized groups showed comparable regeneration at 12 weeks. Silicone tube group showed no regeneration as expected. Muscle force data indicated functional recovery in NG and DFD groups only. Conclusions: This study describes a detergent-free nerve decellularization technique for reconstruction of long-gap nerve injuries. We compared DFD grafts with an established detergent processing technique and found that DFD nerve grafts are successful in promoting regeneration across long-gap peripheral nerve defects as an alternative to existing strategies.

Vasudevan, Srikanth; Huang, Jiying; Botterman, Barry; Matloub, Hani S.; Keefer, Edward

2014-01-01

371

Developmental Changes in Peanut Root Structure during Root Growth and Root-structure Modification by Nodulation  

PubMed Central

Background and Aims Basic information about the root and root nodule structure of leguminous crop plants is incomplete, with many aspects remaining unresolved. Peanut (Arachis hypogaea) forms root nodules in a unique process. Structures of various peanut root types were studied with emphasis on insufficiently characterized lateral roots, changes in roots during their ontogenesis and root modification by nodule formation. Methods Peanut plants were grown in the field, in vermiculite or in filter paper. The taproot, first-order and second-order lateral roots and root nodules were analysed using bright-field and fluorescence microscopy with hand sections and resin sections. Key Results Three root categories were recognized. The primary seminal root was thick, exhibiting early and intensive secondary thickening mainly on its base. It was tetrarch and contained broad pith. First-order lateral roots were long and thin, with limited secondary thickening; they contained no pith. Particularly different were second- and higher-order lateral roots, which were anatomically simple and thin, with little or no secondary growth. Unusual wall ingrowths were visible in the cells of the central part of the cortex in the first-order and second-order lateral roots. The nodule body was formed at the junction of the primary and lateral roots by the activity of proliferating cells derived originally from the pericycle. Conclusions Two morphologically and anatomically distinct types of lateral roots were recognized: long, first-order lateral roots, forming the skeleton of the root system, and thin and short second- and higher-order lateral roots, with an incomplete second state of endodermal development, which might be classified as peanut ‘feeder roots’. Formation of root nodules at the base of the lateral roots was the result of proliferating cell divisions derived originally from the pericycle. PMID:18256023

Tajima, Ryosuke; Abe, Jun; Lee, O. New; Morita, Shigenori; Lux, Alexander

2008-01-01

372

Multi-Electrode Stimulation Of Myelinated Nerve Fibers  

Microsoft Academic Search

\\u000a Patients with a central nervous system injury resulting in total or partial paralysis of extremities often have an intact\\u000a peripheral neuromuscular system. Many attempts were made to restore lost functions by artificial electrical stimulation of\\u000a the peripheral neuromuscular system. In principle, inducing muscle contraction is possible through electrical stimulation\\u000a of:\\u000a \\u000a \\u000a \\u000a \\u000a  \\u000a \\u000a the ventral roots,\\u000a \\u000a \\u000a \\u000a  \\u000a \\u000a the peripheral nerves or\\u000a \\u000a \\u000a \\u000a  

P. H. Veltink; J. A. Alsté; J. Holsheimer

373

Palsies of Cranial Nerves That Control Eye Movement  

MedlinePLUS

... Disorders 4 Palsies of Cranial Nerves That Control Eye Movement These disorders involve paralysis of one of the cranial nerves that control eye movement (the 3rd, 4th, or 6th nerve), impairing the ...

374

Mechanical Loading for Peripheral Nerve Stabilization and Regeneration.  

National Technical Information Service (NTIS)

Peripheral nerve damage is one consequence of injury to the extremities of soldiers by improvised explosive devices (IEDs). The degree of functional recovery from peripheral nerve damage is often poor, particularly for severed nerves. The result can be im...

R. Wilson, S. B. Shah, T. Chuang

2013-01-01

375

Mechanical Loading for Peripheral Nerve Stabilization and Regeneration.  

National Technical Information Service (NTIS)

Peripheral nerve damage is one consequence of injury to the extremities of soldiers by improvised explosive devices (IEDs). The degree of functional recovery from peripheral nerve damage is often poor, particularly for severed nerves. The result can be im...

R. E. Wilson, S. B. Shah, T. Chuang

2012-01-01

376

21 CFR 868.2775 - Electrical peripheral nerve stimulator.  

Code of Federal Regulations, 2013 CFR

...false Electrical peripheral nerve stimulator. 868.2775 ...2775 Electrical peripheral nerve stimulator. (a) Identification. An electrical peripheral nerve stimulator (neuromuscular...effect of anesthetic drugs and gases. (b)...

2013-04-01

377

21 CFR 868.2775 - Electrical peripheral nerve stimulator.  

...false Electrical peripheral nerve stimulator. 868.2775 ...2775 Electrical peripheral nerve stimulator. (a) Identification. An electrical peripheral nerve stimulator (neuromuscular...effect of anesthetic drugs and gases. (b)...

2014-04-01

378

21 CFR 882.1550 - Nerve conduction velocity measurement device.  

...2014-04-01 false Nerve conduction velocity measurement device. 882.1550... § 882.1550 Nerve conduction velocity measurement device. (a) Identification. A nerve conduction velocity measurement device is a...

2014-04-01

379

21 CFR 882.1550 - Nerve conduction velocity measurement device.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Nerve conduction velocity measurement device. 882.1550... § 882.1550 Nerve conduction velocity measurement device. (a) Identification. A nerve conduction velocity measurement device is a...

2011-04-01

380

21 CFR 882.1550 - Nerve conduction velocity measurement device.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Nerve conduction velocity measurement device. 882.1550... § 882.1550 Nerve conduction velocity measurement device. (a) Identification. A nerve conduction velocity measurement device is a...

2012-04-01

381

21 CFR 882.1550 - Nerve conduction velocity measurement device.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Nerve conduction velocity measurement device. 882.1550... § 882.1550 Nerve conduction velocity measurement device. (a) Identification. A nerve conduction velocity measurement device is a...

2010-04-01

382

21 CFR 882.1550 - Nerve conduction velocity measurement device.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Nerve conduction velocity measurement device. 882.1550... § 882.1550 Nerve conduction velocity measurement device. (a) Identification. A nerve conduction velocity measurement device is a...

2013-04-01

383

Forced displacement and women's security in Colombia.  

PubMed

In the protracted Colombian conflict, assistance to internally displaced persons has developed in the context of contradictory political processes. The Colombian government's launching of a transitional justice process in the midst of armed conflict has generated a complex situation displaying both conflict and post-conflict characteristics. The progressive Constitutional Court rulings on internal displacement, in particular the gender-sensitive Auto 092, constitute an attempt to bring together humanitarian interventions and transitional justice measures in a rights-based framework. However, the national government is reluctant to adopt them fully and local realities still hamper their integrated implementation. Displaced women, therefore, remain in an especially vulnerable position. This paper argues that gender-sensitive humanitarian interventions must take into account all of these complexities of scale and political process in order to make legal frameworks more effective at the local level. In these contexts, interventions should pay particular attention to strategies that contribute to transforming pre-existing gender regimes. PMID:20132270

Meertens, Donny

2010-04-01

384

[Localization of peripheral nerves. Success and safety with electrical nerve stimulation].  

PubMed

Peripheral electrical nerve stimulation is one of the standard applications in peripheral regional anesthesia in addition to the ultrasound technique. Among other findings, the visualization of needle and nerve during ultrasound-guided blockade caused a change in clinical practice of peripheral nerve stimulation in the last decade. In the present article old and new aspects of principles and clinical practice of the nerve stimulation technique are presented and summarized in a total clinical concept in order to achieve safe and successful peripheral regional anesthesia using electrical peripheral nerve stimulation. PMID:24715260

Neuburger, M; Schwemmer, U; Volk, T; Gogarten, W; Kessler, P; Steinfeldt, T

2014-05-01

385

Frictional behavior of large displacement experimental faults  

USGS Publications Warehouse

The coefficient of friction and velocity dependence of friction of initially bare surfaces and 1-mm-thick simulated fault gouges (400 mm at 25??C and 25 MPa normal stress. Steady state negative friction velocity dependence and a steady state fault zone microstructure are achieved after ???18 mm displacement, and an approximately constant strength is reached after a few tens of millimeters of sliding on initially bare surfaces. Simulated fault gouges show a large but systematic variation of friction, velocity dependence of friction, dilatancy, and degree of localization with displacement. At short displacement (<10 mm), simulated gouge is strong, velocity strengthening and changes in sliding velocity are accompanied by relatively large changes in dilatancy rate. With continued displacement, simulated gouges become progressively weaker and less velocity strengthening, the velocity dependence of dilatancy rate decreases, and deformation becomes localized into a narrow basal shear which at its most localized is observed to be velocity weakening. With subsequent displacement, the fault restrengthens, returns to velocity strengthening, or to velocity neutral, the velocity dependence of dilatancy rate becomes larger, and deformation becomes distributed. Correlation of friction, velocity dependence of friction and of dilatancy rate, and degree of localization at all displacements in simulated gouge suggest that all quantities are interrelated. The observations do not distinguish the independent variables but suggest that the degree of localization is controlled by the fault strength, not by the friction velocity dependence. The friction velocity dependence and velocity dependence of dilatancy rate can be used as qualitative measures of the degree of localization in simulated gouge, in agreement with previous studies. Theory equating the friction velocity dependence of simulated gouge to the sum of the friction velocity dependence of bare surfaces and the velocity dependence of dilatancy rate of simulated gouge fails to quantitatively account for the experimental observations.

Beeler, N. M.; Tullis, T. E.; Blanpied, M. L.; Weeks, J. D.

1996-01-01

386

Cytoskeleton and Root Hair Growth  

Microsoft Academic Search

\\u000a Root hairs are long tubular outgrowths of root epidermis cell that form to increase the root surface in order to assist in\\u000a the uptake of water and nutrients from soil. Root hair development consists of two distinct processes: root hair initiation\\u000a and tip growth. During both events, the dynamic organization of the cytoskeleton translates local signaling events into a\\u000a focused

Eunsook Park; Andreas Nebenführ

387

Computing Displacements And Strains From Video Images  

NASA Technical Reports Server (NTRS)

Subpixel digital video image correlation (SDVIC) technique for measuring in-plane displacements on surfaces of objects under loads, without contact. Used for analyses of experimental research specimens or actual service structures of virtually any size or material. Only minimal preparation of test objects needed, and no need to isolate test objects from minor vibrations or fluctuating temperatures. Technique implemented by SDVIC software, producing color-graduated, full-field representations of in-plane displacements and partial derivatives with respect to position along both principal directions in each image plane. From representations, linear strains, shear strains, and rotation fields determined. Written in C language.

Russell, Samuel S.; Mcneill, Stephen R.; Lansing, Matthew D.

1996-01-01

388

Displacement sensors using soft magnetostrictive alloys  

NASA Astrophysics Data System (ADS)

We report results on the response of a family of displacement sensors, which are based on the magentostrictive delay line (MDL) technique, using current conductors orthogonal to the MDL. Such sensing technique is based on the change of the magnetic circuit at the acoustic stress point of origin due to the displacement of a soft magnetic material above it. Integrated arrays of sensors can be obtained due to the acoustic delay line technique and they can be used as tactile arrays, digitizers or devices for medical applications (gait analysis etc.), while absence of hysteresis and low cost of manufacturing make them competent in this sector of sensor market.

Hristoforou, E.; Reilly, R. E.

1994-09-01

389

Displacement of crude oil by carbon dioxide  

E-print Network

viscosity of 20 cp until water production from the sand pack was essentially KEY TO SCHEMATIC FOR CO2 FLOOD EOUIPMENT FIGURE 1 1. Core 2. Filter 3. Oil Pump 4. Mercury-Antifreeze Vessel 5. Pressure Gauge 6. Oil Reservoir 7. CO2 Source 8... of crude oil displaced from the three sand packs by CO as a function of pressure was essentially the same. For each of the sand packs three regions were recognized. A pressure region of (1) immiscible crude oil displacement, (2) near miscible crude oil...

Omole, Olusegun

2012-06-07

390

A Safe Lab on Nerve Gases.  

ERIC Educational Resources Information Center

Describes an experiment involving pineapples and gelatin that allows students to investigate the conditions that typically render an enzyme functionless, similar to the effect of nerve gasses. Discusses the materials, procedures, and results, drawing analogies to the effects of a nerve gas. (CW)

Tucker, David C.

1988-01-01

391

Extracranial lower cranial nerve sheath tumors  

Microsoft Academic Search

Objective: The purpose of this article is to review the clinicoradiographic features of lower cranial nerve sheath tumors and to outline surgical approaches that allow the safe and complete resection of these lesions. Methods: Thirteen patients with lower cranial nerve sheath tumors of the infratemporal fossa were surgically treated between 7\\/88 and 10\\/99. A retrospective chart analysis provided details pertaining

John P. Leonetti; Bryan Wachter; Sam J. Marzo; Guy Petruzzelli

2001-01-01

392

Flexible signal generator for facial nerve detection  

Microsoft Academic Search

During surgical intervention on patient face, the facial nerve must be protected. To avoid the risk of its damage, we propose an electronic device that could detect the presence of this nerve. Thanks to its excitability, it was possible therefore to record a noticeable muscular electric reaction on the face. An active stimulating electrode would be placed on the patient

Habib ELKHORCHANI; Hamadi GHARIANI; A. Benhamida; M. Ghorbel

2004-01-01

393

Compression neuropathies of the median nerve  

Microsoft Academic Search

Specific compression syndromes of the median nerve are known in the proximal forearm and at the wrist. Carpal tunnel syndrome is the best known and most common, but pronator teres syndrome and anterior interosseous nerve syndrome also are clinically significant. In this discussion, we review the history, relevant anatomy, diagnosis, and treatment modalities for these compression syndromes.

Jason T. Koo; Robert M. Szabo

2004-01-01

394

Ephaptic Coupling of Myelinated Nerve S. Binczaka  

E-print Network

of this paper, clarifying the nature of conduction on a real nerve and setting the stage for an exploration and discrete limits, clarifying the nature of the conduction process on an isolated nerve axon. Since) interactions between impulses on parallel fibers, which may play a functional role in neural pro- cessing. 1

Eilbeck, Chris

395

Heptadecapeptide Gastrin in the Vagal Nerve  

Microsoft Academic Search

Immunoreactive gastrin was present in vagal nerves from cats, dogs, and human beings. The abdominal portion of the vagus contained gastrin in amounts ranging from 16 to 273 pmol\\/g of nerve tissue (wet weight). The thoracic and cervical portion of the vagi contained only minute amounts of gastrin. Gel chromatography of extracts of human, canine, and feline abdominal vagi monitored

K. Uvnas-Wallensten; J. F. Rehfeld; L.-I. Larsson; B. Uvnas

1977-01-01

396

Nerve growth factor: from neurotrophin to neurokine  

Microsoft Academic Search

Nerve growth factor (NGF) is largely known as a target-derived factor responsible for the survival and maintenance of the phenotype of specific subsets of peripheral neurones and basal forebrain cholinergic nuclei during development and maturation. However, NGF also exerts a modulatory role on sensory, nociceptive nerve physiology during adulthood that appears to correlate with hyperalgesic phenomena occurring in tissue inflammation.

Rita Levi-Montalcini; Stephen D. Skaper; Roberto Dal Toso; Lucia Petrelli; Alberta Leon

1996-01-01

397

Biochemical engineering nerve conduits using peptide amphiphiles.  

PubMed

Peripheral nerve injury is a debilitating condition. The gold standard for treatment is surgery, requiring an autologous nerve graft. Grafts are harvested from another part of the body (a secondary site) to treat the affected primary area. However, autologous nerve graft harvesting is not without risks, with associated problems including injury to the secondary site. Research into biomaterials has engendered the use of bioartificial nerve conduits as an alternative to autologous nerve grafts. These include synthetic and artificial materials, which can be manufactured into nerve conduits using techniques inspired by nanotechnology. Recent evidence indicates that peptide amphiphiles (PAs) are promising candidates for use as materials for bioengineering nerve conduits. PAs are biocompatible and biodegradable protein-based nanomaterials, capable of self-assembly in aqueous solutions. Their self-assembly system, coupled with their intrinsic capacity for carrying bioactive epitopes for tissue regeneration, form particularly novel attributes for biochemically-engineered materials. Furthermore, PAs can function as biomimetic materials and advanced drug delivery platforms for sustained and controlled release of a plethora of therapeutic agents. Here we review the realm of nerve conduit tissue engineering and the potential for PAs as viable materials in this exciting and rapidly advancing field. PMID:22910143

Tan, Aaron; Rajadas, Jayakumar; Seifalian, Alexander M

2012-11-10

398

Malignant peripheral nerve sheath tumors in childhood  

Microsoft Academic Search

Malignant peripheral nerve sheath tumor (MPNST) is an uncommon sarcoma in the pediatric population; however, its presence should be considered in a child with an enlarging or painful soft-tissue mass. Diagnosis of this neoplasm depends on either the demonstration of its origin within a peripheral nerve or the association with a contiguous neurofibroma. We have identified 16 cases of MPNST

Barbara S Ducatman; Bernd W Scheithauer; David G Piepgras; Herbert M Reiman

1984-01-01

399

Contribution of the distal nerve sheath to nerve and muscle preservation following denervation and sensory protection.  

PubMed

The goal of this study was to determine the contribution of the distal nerve sheath to sensory protection. Following tibial nerve transection, rats were assigned to one of the following groups: (1) saphenous-to-tibial nerve neurorrhaphy; (2) saphenous-to-gastrocnemius neurotization; (3) unprotected controls (tibial nerve transection); or (4) immediate common peroneal-to-tibial nerve neurorrhaphy. After a 6-month denervation period and motor reinnervation, ultrastructural, histologic, and morphometric analyses were performed on the distal tibial nerve and gastrocnemius muscle cross-sections. Sensory axons neurotized to muscle maintain existing muscle integrity, as demonstrated by less fibrosis, collagenization, and fat deposition, more than unprotected muscle, and preserve the distribution pattern of fast twitch fibers. However, neurorrhaphy of the sensory nerve to the distal tibial nerve (involving the distal nerve sheath) improves existing endoneurial sheath structure, demonstrated by reduced collagen, and enhances regeneration, shown by improved axon-to-Schwann cell coupling and increased axon area. The authors conclude that sensory protection of muscle does not require the distal nerve sheath, but that preservation of the distal sheath may contribute to enhanced nerve regeneration. PMID:15672322

Veltri, Karen; Kwiecien, Jacek M; Minet, Wyatt; Fahnestock, Margaret; Bain, James R

2005-01-01

400

Noise analysis and improvement of displacement vector estimation from angular displacements  

PubMed Central

Elastography or elasticity imaging techniques typically image local strains or Young’s modulus variations along the insonification direction. Recently, techniques that utilize angular displacement estimates obtained from multiple angular insonification of tissue have been reported. Angular displacement estimates obtained along different angular insonification directions have been utilized for spatial-angular compounding to reduce noise artifacts in axial-strain elastograms, and for estimating the axial and lateral components of the displacement vector and the corresponding strain tensors. However, these angular strain estimation techniques were based on the assumption that noise artifacts in the displacement estimates were independent and identically distributed and that the displacement estimates could be modeled using a zero-mean normal probability density function. Independent and identically distributed random variables refer to a collection of variables that have the same probability distribution and are mutually independent. In this article, a modified least-squares approach is presented that does not make any assumption regarding the noise in the angular displacement estimates and incorporates displacement noise artifacts into the strain estimation process using a cross-correlation matrix of the displacement noise artifacts. Two methods for estimating noise artifacts from the displacement images are described. Improvements in the strain tensor (axial and lateral) estimation performance are illustrated utilizing both simulation data obtained using finite-element analysis and experimental data obtained from a tissue-mimicking phantom. Improvements in the strain estimation performance are quantified in terms of the elastographic signal-to-noise and contrast-to-noise ratios obtained with and without the incorporation of the displacement noise artifacts into the least-squares strain estimator. PMID:18561677

Chen, Hao; Varghese, Tomy

2008-01-01

401

Sensory recovery following decellularized nerve allograft transplantation for digital nerve repair.  

PubMed

This study reported preliminary clinical experience of using decelluarised nerve allograft material for repair of digital nerve defect in five hand injury patients. From October 2009 to July 2010, five patients with traumatic nerve defect were treated with nerve repair using AxoGen® nerve allograft (AxoGen Inc, Alachua, FL) in California Hospital Medical Center. All patients were followed at least for 12 months, and sensory recovery and signs of infection or rejection were documented by a hand therapist. Average two-point discrimination was 6 mm, and average Semmes-Weinstein Monofilaments test was 4.31. No wound infections or signs of rejections were observed at wound site. All patients reported sensory improvement during the follow-up period after operation. It is believed that decellularised nerve allografts may provide a readily available option for repair of segmental nerve defect. PMID:23848418

Guo, Yang; Chen, Gary; Tian, Guanglei; Tapia, Carla

2013-12-01

402

Displacement of organelles in plant gravireceptor cells by vibrational forces and ultrasound.  

NASA Astrophysics Data System (ADS)

Plant gravity perception can be studied by displacing statoliths inside receptor cells by forces other than gravity. Due to mechanical heterogeneity of statocytes various ponderomotive forces can be used for this purpose. In a plant subjected to non- symmetric vibrations statoliths experience inertial force proportional to the difference between their density and that of cytoplasm and to the instantaneous acceleration of the cell. This force causes cyclic motion of statoliths relative to cytoplasm and, depending on the profile of oscillations, can result in a net displacement of them (due to complex rheology of the cell interior), similar to sedimentation. This can be described as "vibrational" ponderomotive force acting on the statoliths. Vertically growing Arabidopsis seedlings, subjected to horizontal, sawtooth shaped oscillations (250 Hz, 1.5 mm amplitude), showed 17+/-2o root curvature toward and shoot curvature of 11+/-3o against the stronger acceleration. When the polarity of the oscillations was reversed, the direction of curvature of shoots and roots was also reversed. Control experiments with starchless mutants (TC7) produced no net curvature, which indicates that dense starch-filled amyloplasts are needed for the effect. These control experiments also eliminate touch-induced reactions or other side-effects as the cause of the curvature. Linum roots curved 25+/-7o . Ceratodon protonemata subjected to the same oscillations have shown displacement of plastids and curvature consistent with the pattern observed during graviresponse: positively gravitropic wwr mutant curved in the direction of the plastid displacement, WT curved in the opposite direction. Acoustic ponderomotive forces, originating from transfer of a sonic beam momentum to the medium due to sound scattering and attenuation in a mechanically heterogeneous system, also can displace statoliths. Vertical flax seedlings curved away from the ultrasonic source (800 kHz, 0.1 W/cm2 ) presumably as a reaction to amyloplasts displacement by acoustic forces. Besides investigating the graviperception mechanism, vibrational and acoustic forces can serve as tools for analyzing mechanical properties of cell interior. Practical applications of this technology could include providing directional stimuli for plants in microgravity by low doses of vibrations. Vibrations present on board of spacecraft may have vectorial effects on plants and other organisms, and their influence should be assessed.

Kuznetsov, O.; Nechitailo, G.; Kuznetsov, A.

403

The Epicardial Neural Ganglionated Plexus of the Ovine Heart: Anatomical Basis for Experimental Cardiac Electrophysiology and Nerve Protective Cardiac Surgery  

PubMed Central

Summary BACKGROUND The sheep is routinely used in experimental cardiac electrophysiology and surgery. OBJECTIVE We aimed at (1) ascertaining the topography and architecture of the ovine epicardial neural plexus (ENP), (2) determining the relationships of the ENP with the vagal and sympathetic cardiac nerves and ganglia, and (3) evaluating gross anatomical differences and similarities among ENPs in humans, sheep and other species. METHODS The ovine ENP, extrinsic sympathetic and vagal nerves were revealed histochemically for acetylcholinesterase on whole heart and/or thorax-dissected preparations from 23 newborn lambs with subsequent examination by a stereomicroscope. RESULTS The intrinsic cardiac nerves extend from the venous part of the ovine heart hilum (HH) along the roots of the cranial (superior) caval and left azygos veins to both atria and ventricles via five epicardial routes; i.e. the dorsal right atrial (DRA), middle (MD), left dorsal (LD), right ventral (VR) and ventral left atrial (VLA) nerve subplexuses. Intrinsic nerves proceeding from the arterial part of the HH along the roots of the aorta and pulmonary trunk extend exclusively into the ventricles as the right and left coronary subplexuses. The DRA, RV, and MD subplexuses receive the main extrinsic neural input from the right cervicothoracic and the right thoracic sympathetic T2, T3 ganglia, as well as from the right vagal nerve. The LD is supplied by sizeable extrinsic nerves from the left thoracic T4-T6 sympathetic ganglia and the left vagal nerve. Sheep hearts contained on average 769±52 epicardial ganglia. Cumulative areas of epicardial ganglia on the root of the cranial vena cava and on the wall of the coronary sinus were the largest of all regions (p<0.05). CONCLUSION Despite substantial interindividual variability in the morphology of the ovine ENP, the right-sided epicardial neural subplexuses supplying the sinuatrial and atrioventricular nodes are mostly concentrated at a fat pad between the right pulmonary veins and the cranial vena cava. This is in sharp contrast with a solely left lateral neural input to the human atrioventricular node which extends mainly from the LD and MD subplexuses. The abundance of epicardial ganglia distributed widely along the ovine ventricular nerves over respectable distances below the coronary groove implies a distinctive neural control of the ventricles in human and sheep hearts. PMID:20197118

Saburkina, Inga; Rysevaite, Kristina; Pauziene, Neringa; Mischke, Karl; Schauerte, Patrick; Jalife, Jose; Pauza, Dainius H.

2011-01-01

404

Histological assessment in peripheral nerve tissue engineering  

PubMed Central

The histological analysis of peripheral nerve regeneration is one of the most used methods to demonstrate the success of the regeneration through nerve conduits. Nowadays, it is possible to evaluate different parameters of nerve regeneration by using histological, histochemical, immunohistochemical and ultrastructural techniques. The histochemical methods are very sensible and are useful tools to evaluate the extracellular matrix remodeling and the myelin sheath, but they are poorly specific. In contrast, the immunohistochemical methods are highly specific and are frequently used for the identification of the regenerated axons, Schwann cells and proteins associated to nerve regeneration or neural linage. The ultrastructural techniques offer the possibility to perform a high resolution morphological and quantitative analysis of the nerve regeneration. However, the use of a single histological method may not be enough to assess the degree of regeneration, and the combination of different histological techniques could be necessary. PMID:25374585

Carriel, Víctor; Garzón, Ingrid; Alaminos, Miguel; Cornelissen, Maria

2014-01-01

405

Update on nerve repair by biological tubulization  

PubMed Central

Many surgical techniques are available for bridging peripheral nerve defects. Autologous nerve grafts are the current gold standard for most clinical conditions. In selected cases, alternative types of conduits can be used. Although most efforts are today directed towards the development of artificial synthetic nerve guides, the use of non-nervous autologous tissue-based conduits (biological tubulization) can still be considered a valuable alternative to nerve autografts. In this paper we will overview the advancements in biological tubulization of nerve defects, with either mono-component or multiple-component autotransplants, with a special focus on the use of a vein segment filled with skeletal muscle fibers, a technique that has been widely investigated in our laboratory and that has already been successfully introduced in the clinical practice. PMID:24606921

2014-01-01

406

Burma: Displaced Karens. Like Water on the Khu Leaf  

Microsoft Academic Search

War disrupts the normal relationship between people and place. Displaced by war, people must adapt to survive, both physically and socially. When people are displaced for a long time, these adaptations become normal; thus displacement starts as an aberration but becomes a constant way of life. In eastern Burma, 'normal' displacement has led to significant changes in the political, cultural

Chris Cusano

1990-01-01

407

Facial nerve outcome after acoustic neuroma surgery: a study from the era of cranial nerve monitoring.  

PubMed

The introduction of intraoperative cranial nerve monitoring in posterior fossa surgery has greatly aided the surgeon in identification and anatomic preservation of cranial nerves. As a result, the long-term function of the facial nerve continues to improve after removal of acoustic neuroma. Herein, we report our long-term (1 year or greater) facial nerve outcome in 129 patients who underwent surgical removal of their acoustic neuromas with the aid of intraoperative neurophysiologic monitoring between 1986 and 1990. The facial nerve was anatomically preserved in 99.2% of the patients, and 90% of all the patients had grade 1 or 2 facial nerve function 1 year after surgery. Long-term facial function was inversely correlated with the size of tumor (chi-squared, p < 0.02) and was not related to the side of tumor, the age and sex of the patient, or the surgical approach. In a comparison among tumor groups matched for size, no statistically significant difference in facial nerve outcome between the translabyrinthine and retrosigmoid approaches was detected. The proximal facial nerve stimulation threshold at the end of surgical removal was predictive of long-term facial nerve function (analysis of variance, p < 0.02). At 1 year, 98% (87 of 89) of the patients with electrical thresholds of 0.2 V or less had grade 1 or 2 facial nerve function compared with only 50% (8 of 16) of those with thresholds between 0.21 and 0.6 V. In the era of cranial nerve monitoring, patients can be better advised about long-term facial nerve outcome after surgical intervention. Preoperatively, the size of the tumor is the most critical factor in predicting long-term facial function. Postoperatively, the proximal seventh nerve stimulation threshold at the end of the surgical procedure can be used as one prognostic measure of long-term facial nerve function. PMID:7970793

Lalwani, A K; Butt, F Y; Jackler, R K; Pitts, L H; Yingling, C D

1994-11-01

408

Multifunctional Silk Nerve Guides for Axon Outgrowth  

NASA Astrophysics Data System (ADS)

Peripheral nerve regeneration is a critical issue as 2.8% of trauma patients present with this type of injury, estimating a total of 200,000 nerve repair procedures yearly in the United States. While the peripheral nervous system exhibits slow regeneration, at a rate of 0.5 mm -- 9 mm/day following trauma, this regenerative ability is only possible under certain conditions. Clinical repairs have changed slightly in the last 30 years and standard methods of treatment include suturing damaged nerve ends, allografting, and autografting, with the autograft the gold standard of these approaches. Unfortunately, the use of autografts requires a second surgery and there is a shortage of nerves available for grafting. Allografts are a second option however allografts have lower success rates and are accompanied by the need of immunosuppressant drugs. Recently there has been a focus on developing nerve guides as an "off the shelf" approach. Although some natural and synthetic guidance channels have been approved by the FDA, these nerve guides are unfunctionalized and repair only short gaps, less than 3 cm in length. The goal of this project was to identify strategies for functionalizing peripheral nerve conduits for the outgrowth of neuron axons in vitro . To accomplish this, two strategies (bioelectrical and biophysical) were indentified for increasing axon outgrowth and promoting axon guidance. Bioelectrical strategies exploited electrical stimulation for increasing neurite outgrowth. Biophysical strategies tested a range of surface topographies for axon guidance. Novel methods were developed for integrating electrical and biophysical strategies into silk films in 2D. Finally, a functionalized nerve conduit system was developed that integrated all strategies for the purpose of attaching, elongating, and guiding nervous tissue in vitro. Future directions of this work include silk conduit translation into a rat sciatic nerve model in vivo for the purpose of repairing long (> 3 cm) peripheral nerve gaps.

Tupaj, Marie C.

409

Variable-Displacement Hydraulic Drive Unit  

NASA Technical Reports Server (NTRS)

Hydraulic power controlled through multiple feedback loops. In hydraulic drive unit, power closely matched to demand, thereby saving energy. Hydraulic flow to and from motor adjusted by motor-control valve connected to wobbler. Wobbler angle determines motor-control-valve position, which in turn determines motor displacement. Concept applicable to machine tools, aircraft controls, and marine controls.

Lang, D. J.; Linton, D. J.; Markunas, A.

1986-01-01

410

Estimation of optical flow for large displacements  

Microsoft Academic Search

In this paper we present a new method to estimate optical flow for large displacements. It is based on prediction of global flow field parameters, performs better than multi- resolution estimation methods and has been verified using standard test sequences as well as real-world data. Global flow field parameters can be estimated from optical flow measurements in all flow regions.

Torsten Radtke; Horst Salzwedel

2001-01-01

411

Displacement of Bilirubin from Albumin by Berberine  

Microsoft Academic Search

A study was made of the effect of berberine, the major ingredient of the Chinese herb huanglian (coptis chinensis) reported to pose some risk for kernicterus among jaundiced newborn Chinese infants, on the protein binding of bilirubin, using the peroxidase kinetic method. Berberine was found in vitro, as to its displacing effect on a molar basis, to be about tenfold

Eli Chan

1993-01-01

412

Television and Schooling: Displacement and Distraction Hypotheses.  

ERIC Educational Resources Information Center

Research on two hypotheses regarding television's possible negative effect on children's academic achievement is reviewed. A lack of support is found for the displacement hypothesis (time spent with television is taken away from more academically beneficial activities) and limited support for the distraction hypothesis (exposure to television…

Roberts, Donald F.; And Others

1993-01-01

413

Character displacement and the origins of diversity  

PubMed Central

In The Origin of Species, Darwin proposed his ‘principle of divergence of character’ (a process now termed ‘character displacement’) to explain how new species arise and why they differ from one other phenotypically. Darwin maintained that the origin of species, and the evolution of differences between them, is ultimately caused by divergent selection acting to minimize competitive interactions between initially similar individuals, populations, and species. Here, we examine the empirical support for the various claims that constitute Darwin’s principle, specifically that: (1) competition promotes divergent trait evolution; (2) the strength of competitively mediated divergent selection increases with increasing phenotypic similarity between competitors; (3) divergence can occur within species; and (4) competitively mediated divergence can trigger speciation. We also explore aspects that Darwin failed to consider. In particular, we describe how: (1) divergence can arise from selection acting to lessen reproductive interactions; (2) divergence is fueled by the intersection of character displacement and sexual selection; and (3) phenotypic plasticity may play a key role in promoting character displacement. Generally, character displacement is well supported empirically, and it remains a vital explanation for how new species arise and diversify. PMID:21043778

Pfennig, David W.; Pfennig, Karin S.

2012-01-01

414

Maximizing Displacement: Mass, Volume and Density  

NSDL National Science Digital Library

This is an indoor lab that uses a boat simulation to demonstrate the concepts of mass, volume and density, and their relationship to displacement. It is a problem solving activity that encourages student creativity resulting in a variety of valid solutions.

415

Ko Displacement Theory for Structural Shape Predictions  

NASA Technical Reports Server (NTRS)

The development of the Ko displacement theory for predictions of structure deformed shapes was motivated in 2003 by the Helios flying wing, which had a 247-ft (75-m) wing span with wingtip deflections reaching 40 ft (12 m). The Helios flying wing failed in midair in June 2003, creating the need to develop new technology to predict in-flight deformed shapes of unmanned aircraft wings for visual display before the ground-based pilots. Any types of strain sensors installed on a structure can only sense the surface strains, but are incapable to sense the overall deformed shapes of structures. After the invention of the Ko displacement theory, predictions of structure deformed shapes could be achieved by feeding the measured surface strains into the Ko displacement transfer functions for the calculations of out-of-plane deflections and cross sectional rotations at multiple locations for mapping out overall deformed shapes of the structures. The new Ko displacement theory combined with a strain-sensing system thus created a revolutionary new structure- shape-sensing technology.

Ko, William L.

2010-01-01

416

Extracting gravity line displacement from stabilographic recordings  

Microsoft Academic Search

Three algorithms for determining gravity line (GL) location from center of pressure (COP) and horizontal force (Fx) recordings are suggested. The algorithms are designed to study upright standing posture and are based on the following premises: (a) the foot(feet) is a solid body and does not move, (b) the axis of rotation of the ankle joint does not displace, and

Deborah L. King; Vladimir M. Zatsiorsky

1997-01-01

417

A Personal Appearance Program for Displaced Homemakers.  

ERIC Educational Resources Information Center

A career counseling program evaluated the self-esteem of 28 displaced homemakers, then presented 3 sessions on the importance of personal appearance in hiring practices, wardrobe management, nonverbal communication, professional image, and self-concept. Analysis of participant evaluations indicated improved levels of control and confidence and…

Fiore, Ann Marie; De Long, Marilyn Revell

1990-01-01

418

THE SYMPLECTIC DISPLACEMENT ENERGY AUGUSTIN BANYAGA  

E-print Network

THE SYMPLECTIC DISPLACEMENT ENERGY AUGUSTIN BANYAGA , DAVID E. HURTUBISE, AND PETER SPAETH Abstract , DAVID E. HURTUBISE, AND PETER SPAETH for all f Symp(M, ) = { Diff(M) | = }. This follows from to the identity. It was proved recently by Buss and Leclercq [6] that the restriction of · HL to Ham

Hurtubise, David E.

419

Improvement in nerve regeneration through a decellularized nerve graft by supplementation with bone marrow stromal cells in fibrin.  

PubMed

Acellular nerve grafting is often inferior as well as an inadequate alternative to autografting for the repair of long gaps in peripheral nerves. Moreover, the injection method is not perfect. During the injection of cells, the syringe can destroy the acellular nerve structure and the limited accumulation of seed cells. To resolve this problem, we constructed a nerve graft by acellular nerve grafting. Bone marrow-mesenchymal stromal cells (BM-MSCs) were affixed with fibrin glue and injected inside or around the graft, which was then used to repair a 15-mm nerve defect in rats. The acellular nerve graft maintained its structure and composition, and its tensile strength was decreased, as determined by two-photon microscopy and a tensile testing device. In vitro, MSCs embedded in fibrin glue survived and secreted growth factors such as nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF). We repaired 15-mm Sprague-Dawley rat sciatic nerve defects using this nerve graft construction, and MSCs injected around the graft helped improve nerve regeneration and functional recovery of peripheral nerve lesions as determined by functional analysis and histology. Therefore, we conclude that supplying MSCs in fibrin glue around acellular nerves is successful in maintaining the nerve structure and can support nerve regeneration similar to the direct injection of MSCs into the acellular nerve for long nerve defects but may avoid destroying the nerve graft. The technique is simple and is another option for stem cell transplantation. PMID:23128095

Zhao, Zhe; Wang, Yu; Peng, Jiang; Ren, Zhiwu; Zhang, Li; Guo, Quanyi; Xu, Wenjing; Lu, Shibi

2014-01-01

420

Differentiation of idiopathic spinal cord herniation from CSF-isointense intraspinal extramedullary lesions displacing the cord.  

PubMed

Focal spinal cord displacement can be caused by idiopathic spinal cord herniation (ISCH), in which the cord protrudes through a dural defect into the epidural space, causing cord displacement and tethering. ISCH is uncommon and often is misdiagnosed initially, which results in delayed management. ISCH can be mimicked by space-occupying cerebrospinal fluid (CSF)-isointense intraspinal extramedullary lesions, such as epidermoid cysts or teratomas, intradural arachnoid cysts, epidural hematomas or abscesses, cystic nerve sheath tumors, synovial or Tarlov cysts, meningoceles, and pseudomeningoceles.